WorldWideScience
 
 
1

Research on work roll thermal crown in cold rolling mill  

Science.gov (United States)

The factors which have influence on the work roll thermal crown in cold strip rolling are discussed. The heat transferring in three directions (radial axis and circumference) were considered for calculating the work roll thermal deformation. Therefore, it is a three dimensions unstable system for the work roll temperature calculation. The plastic deformation work and friction heat are calculated by the divided element and digital integration method. The simplified calculation model is built for the heat transferring along work roll. There are four zones for work roll heat transferring: roll gap zone air cooling zone emulsion zone rolls contact zone. The heat transferring between the zones is decided by the temperature difference. The inter temperature field and thermal deformation of work roll can be calculated by two-dimension finite difference method. The work roll temperature and thermal crown of actual application cold rolling mill are analyzed by the model. By the comparison between calculated values and measured values, the work roll thermal calculation model can meet the accuracy requirement of on-line control.

Song, Lei; Shen, Mingang; Chen, Xuebo; Wang, Junsheng

2013-05-01

2

Stress and accidental defect detection on rolling mill rolls  

International Nuclear Information System (INIS)

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

3

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

4

Technological design for rolling uranium rod by Y-type rolling mill with three rollers  

International Nuclear Information System (INIS)

The fundamental characteristics of Y-type rolling mill with three rollers and the methods for designing and calculating the grooves are described. The feasibility of producing metallic uranium rod is substantiated by the experiment in continuous rolling. The advantage of this process in rolling metallic uranium rod is analysed

5

Investigation of unbalanced mass of a work roll in a cold rolling mill  

Energy Technology Data Exchange (ETDEWEB)

An abrasion due to continuous friction between a work roll and strip causes the mass of the work roll to be unbalanced in the rolling process. We developed a mathematical model for the rolling mill considering the unbalanced mass and verified the model experimentally. The work roll was approximated as a rigid rotor with eccentricity, and the effect of the unbalanced mass on chatter vibration was investigated. The joint forces computed by quasistatic analysis were applied to the work roll in the rolling mill. Transient responses were obtained, and frequency analysis was performed by solving equations of motion using a direct integration method. Horizontal vibrations were more strongly affected by eccentricity than vertical vibrations. In the horizontal direction, a small eccentricity of 1% of the work roll radius considerably increased the amplitude of the chatter frequency.

Kim, Youngdeuk; Park, Hyunchul [Pohang Univ. of Science and Technology Pohang (Korea, Republic of); Kim, Chang Wan [Konkuk Univ., Seoul (Korea, Republic of)

2012-04-15

6

Investigation of unbalanced mass of a work roll in a cold rolling mill  

International Nuclear Information System (INIS)

An abrasion due to continuous friction between a work roll and strip causes the mass of the work roll to be unbalanced in the rolling process. We developed a mathematical model for the rolling mill considering the unbalanced mass and verified the model experimentally. The work roll was approximated as a rigid rotor with eccentricity, and the effect of the unbalanced mass on chatter vibration was investigated. The joint forces computed by quasistatic analysis were applied to the work roll in the rolling mill. Transient responses were obtained, and frequency analysis was performed by solving equations of motion using a direct integration method. Horizontal vibrations were more strongly affected by eccentricity than vertical vibrations. In the horizontal direction, a small eccentricity of 1% of the work roll radius considerably increased the amplitude of the chatter frequency

7

Development of a rational roll pass design for a rolling mill using performance criteria  

Science.gov (United States)

A new technique is developed to analyze the roll pass design of a section rolling mill. Metal forming nonuniformity and efficiency coefficients, which determine the degree of working of a metal microstructure in rolling of section bars, are used as performance criteria. The system of roll passes intended for the production of a round bar 28 mm in diameter is used as an example to analyze possible deformation schemes and the advantages and disadvantages of each scheme.

Vinogradov, A. I.; Timofeeva, M. A.; Korol', S. O.; Traino, A. I.

2013-01-01

8

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

9

Rolling of molybdenum and niobium tubes on cold-rolling mill with high stiff stand  

International Nuclear Information System (INIS)

To develop the technique of tube production the process of rolling is studied and comparative evaluation of the structure formed is carried out. It is shown that billets of rods deformed by screw rolling have the improved plastic properties and are deformed on cold-rolling mill (CRM) with a high degree of reduction without defect formation. High stiff stand of the CRM permits to produce high-quality molybdenum tubes

10

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

11

Analysis of roll stack deflection in a hot strip mill  

Directory of Open Access Journals (Sweden)

Full Text Available 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 effect to reduce the amount of the stack deflection. The results from the sensitivity analysis of the roll width on roll deflection are also described.

Sudipta Sikdar

2007-09-01

12

Analysis of roll stack deflection in a hot strip mill  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 us [...] ed 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 effect to reduce the amount of the stack deflection. The results from the sensitivity analysis of the roll width on roll deflection are also described.

Sudipta, Sikdar; Shylu, John; Ashwin, Pandit; Raju, Dasu.

13

Analysis of roll stack deflection in a hot strip mill  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english 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 us [...] ed 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 effect to reduce the amount of the stack deflection. The results from the sensitivity analysis of the roll width on roll deflection are also described.

Sudipta, Sikdar; Shylu, John; Ashwin, Pandit; Raju, Dasu.

2007-09-01

14

Microbiological treatment of recirculating wastewater from cleaning rolls in a rolling mill.  

Science.gov (United States)

In industry, the use of biological methods for cleaning wastewater is increasing. The number of airborne Gram-negative bacteria was high in relation to the use of high pressure water in a rolling mill using recirculated water for cleaning rolls. Analyzing the total amount and species of microorganisms indicates whether they are emitted from a polluted source or consist of the normal airborne flora. PMID:8116637

Lundholm, M; Grönqvist, B

1994-01-01

15

Development and investigation of a two-line tube rolling on the KhPT-55 cold tube rolling mill  

International Nuclear Information System (INIS)

A change for the two-thread rolling accomplished at the Pervoural'skij new-tube work in 1969 is an effective way of increasing the productivity of the functioning mills of cold tube rolling. A brief description and technological characteristics of the modified KHPT-55 rolling-mill are given. The mill started to roll two steel tubes simultaneously for the first time. The results of an experimental study of the two-thread and one-thread rolling-mills including the determination of the power-strength parameters are presented. The structural shortcomings of the initial model eliminated in the process of operation are described. Despite the decrease in the feed and the number of double passes per minute and some increase in idling, the rolling-mill productivity increased 1.5 times

16

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

17

[Occupational skin diseases in rolling-mill workers in aluminum mills].  

Science.gov (United States)

Some data on frequency and nature of occupational dermatological diseases and stigmata, as well as the results of epicutaneous allergy tests done with occupational allergens with 234 rollers in the rolling mills of the aluminum mill in Razine, near Sibenik are presented. We have recorded occupational dermatose in 44 rollers (18.8%). In the hot rolling mill, sixty rollers have undergone the test and there was 16 recorded cases of occupational dermatose (26.6%). In the cold rolling mill, 174 rollers have undergone the test, and the occupational dematose was recorded in 28 rollers (16.1%). Positive epicutaneous allergic reaction on occupational allergens was found in 5 (2.1%) rollers. Occupational stigmata are somewhat more frequent in the hot rolling mill and their ratio is from 48-100%, whereas in the cold rolling mill they are somewhat less frequent ranging between 40.3 and 97.0% of rollers. PMID:2528044

Bali?, J; Klarica, J

1989-01-01

18

A contact-type tensionmeter for hot rolling mills  

Science.gov (United States)

To improve the hot rolled strip quality and operational stability, a novel tensionmeter based on lever principle is developed which inspects latent waves and provides real references for flatness control in hot rolling process. The contact-type tensionmeter including two segmented rolls can get the transverse tension distribution along the strip width. Tension profile is deduced by different ratio of four force values from the embedded force sensors in tensionmeter system. The compact mechanical structure ensures the tensionmeter's robust stability in hot rolling process, standard hardware and software for data acquisition make the system easy to operate and maintain. The trails have proven tensionmeter successful in improving both strip flatness and mill performance.

Zhao, Xiaoyan; Zhang, Zhaohui; Sun, Yikang; Wang, Jun; Que, Cheng

2008-12-01

19

Digital technology for radiometric thickness gages in rolling mills  

International Nuclear Information System (INIS)

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

20

An application of digital filter to roll eccentricity control on strip rolling mill  

International Nuclear Information System (INIS)

Roll eccentricity on strip thickness gauge has been a vital issue among rolling engineers. We present the results of basic consideration of roll eccentricity and its effects on strip thickness gauge. We analyzed some solutions comparatively and show a new application of digital filtering technology. Digital filter that estimates directly the eccentricity waveform along with back up roll rotation has only little effect on thickness gauge. Any type of roll force automatic gauge control works without any inconsistency. The proposed roll eccentricity control is simple and can be installed in any real time programmable logic controllers. (author)

 
 
 
 
21

Tribological Testing of Anti-Adhesive coatings for Cold Rolling Mill Rolls--Application to TiN-Coated Rolls  

International Nuclear Information System (INIS)

Roll life is a major issue in cold strip rolling. Roll wear may result either in too low roll roughness, bringing friction below the minimum requested for strip entrainment; or it may degrade strip surface quality. On the contrary, adhesive wear and transfer (''roll coating'', ''pick up'') may form a thick metallic deposits on the roll which increases friction excessively and degrades strip surface again [1]. The roll surface, with the help of a materials-adapted lubricant, must therefore possess anti-wear and anti-adhesive properties. Thus, High Speed Steeel (HSS) rolls show superior properties compared with standard Cr-steel rolls due to their high carbide surface coverage. Another way to improve wear and adhesion properties of surfaces is to apply hard metallic (hard-Cr) or ceramic coatings. Chromium is renowned for its excellent anti-wear and anti-adhesive properties and may serve as a reference. Here, as a first step towards alternative, optimised coatings, a PVD TiN coating has been deposited on tool steels, as previous attempts have proved TiN to be rather successful in cold rolling experiments [2,3]. Different tribological tests are reported here, giving insight in both anti-adhesive properties and fatigue life improvement.

22

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

23

Methods for increasing the service durability of cold rolling mill rolls  

Science.gov (United States)

Various conditions of heat treatment of low-alloy pearlitic steels, medium-alloy martensitic and pearlitic-martensitic steels, and high-alloy ledeburitic roll steels are studied. Practical recommendations for increasing the quality of roll tools are developed. They consist of the application of cyclic heat treatment, including cyclic subzero treatment. The increase in the service durability of rolls after the implementation of these recommendations under industrial conditions is analyzed.

Yusupov, V. S.; Doronin, I. V.; Antipov, V. I.; Rusakov, A. D.; Alekseev, P. A.; Lukina, Yu. A.

2011-11-01

24

Optimize cold sector material flow of a steel rolling mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Baudet, Alvaro

2010-01-01

25

Modelling and control of a hot rolling mill  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in english In this paper, a real application of optimal control of a hot rolling mill is presented. It is used the state space model formulation in the minimization of the strip thickness variations. It is presented the simulation results of the control model, which is compared with industrial real data from p [...] rocess controled by traditional techniques. The results of the simulations lead to a less output thickness variations compared with the real industrial data.

F. G., Rossomando; J., Denti Filho.

26

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

Directory of Open Access Journals (Sweden)

Full Text Available The development of a possible slip line field (slf for theoretical calculations of the deforming pressure (load in a second pass of a lubricated cold rolling sheet mill and validation using values from an aluminium sheet rolling mill was done in this work. This will be relevant in the manufacturing industries providing an easy method for determining necessary applied rolling load. Experimental rolling was carried out to observe the shear lines in the deformation field. Construction of possible slip line field model was developed adhering strictly to assumptions of rigid plastic model. Calculation of the deforming force/load was achieved using Hencky’s equation. Results showed that the load calculations for constructed slip line field using aluminium sheet rolling as an example tallied with values obtained from Tower Aluminium rolling mill. Slip line fields constructed for the second pass described adequately the rolling pressure in the cold rolling process, giving a valid solution of the exact load estimates on comparison with the industrial load values. Roll pressure along the arc of contact rose fairly linearly from the entrance to a maximum at the exit point. This work showed that slf for the first pass in a cold rolling mill cannot be used for subsequent passes; it requires construction of slfs for each pass in the cold rolling process.

Oluleke O. Oluwole

2011-12-01

27

Calculation and experimental technique of determination of rolling procedure for cold-rolling tube mills  

International Nuclear Information System (INIS)

Calculation and experimental technique of determination of tube cold rolling procedure has been developed. Rolling procedure based on the usage of regression equation epsilon=1.24 psi, where psi is the relative reduction of area, delta-permissible reduction during rolling, has been tested on 08Kh18N10T steel. The effect of tube geometry, tool calibration parameters, lubrication conditions etc. on metal deformability in taking into account experimentally. The use of the technique proposed has allowed to shorten the time of mastering of the production of tubes from different steels

28

High-pressure roll mill comminution of heterogeneous multicomponent feeds  

Energy Technology Data Exchange (ETDEWEB)

Highly complex comminution phenomena can occur in the grinding of multi-component feeds such as ores, coal or mill feeds. High-pressure roll mill comminution of heterogeneous multicomponent feeds was simulated with artificial limestone-quartzite mixtures using a piston-die press. The influence of heterogeneous interactions between components of the mixture on grinding path, energy utilization and energy split have been examined. Primary fractures are governed by differential fracture strength and attrition resistance of the components at heterogeneous contacts; subsequent secondary and tertiary fracture events are governed by coarse-fine interactions in the particle-bed. The weaker component is preferentially ground out of the feed size fraction and concentrates in the fines. Energy split among the components in the mixture is a function of their relative fracture strengths. It doubles for limestone and decreases by a factor of 5 for quartzite over the entire range of the mixing ratio.

Gutsche, O.

1995-12-31

29

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

Directory of Open Access Journals (Sweden)

Full Text Available This study focuses on the necessity of designing state observers to be used in controller synthesis for rolling processes. This is motivated by the fact that using several kinds of sensors for measuring all of process variables is technically and economically avoided. On the other hand, using exact measurement in feedback control systems could considerably improve the quality of products. In other word, there is a trade-off between high quality and the implementation limitations, managed here by developing rolling state observers. The proposed observers estimate the states not measured directly by the installed sensors. This technique is applicable to both hot rolling and cold rolling processes. Simulation results demonstrate the performance of the proposed estimation algorithm.

Hamid R. Koofigar

2011-09-01

30

Production of stainless steel tubes at 140 tube-rolling mill  

International Nuclear Information System (INIS)

At the tube-rolling aggregate of the 140 tube-rolling mill the process has been investigated of tube rolling in size of 146x12-16 mm from the 08Kh18N10T steel for cold conversion. Both, the hot-rolled and the cold-rolled tubes have stood the intercrystallite corrosion test and fully conform to the necessary requirements. At the TRA-140 the production of tubes in size of 146x12-16 mm from the stainless steel has been mastered

31

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

32

Development of alignment-guidance device for grooved roll mill using parallel projection imaging technique  

Science.gov (United States)

The accuracy in the arrangement of grooved rolls for the finishing rolling mill is of large importance for the good roundness of the bar steel product supplied to the precision machinery components such as the bearing of the high speed motor. Combining telecentric optics, silhouette image processing techniques, and statistical data processing allowed the development of the quantitative alignment guidance technique of the grooved rolls. The developed system demonstrated a high measuring accuracy and was seen to have practical use.

Kodama, Toshifumi; Iwata, Teruhisa; Yamagami, Daisaku; Takagi, Keiji

2013-04-01

33

Research on roll wear of 2050mm hot strip finishing train (CVC Mill) of Baosteel  

International Nuclear Information System (INIS)

In this paper, the general characteristics and affecting factors of work and backup rolls wear of finishing train were analyzed. Taking the CVC finishing mills of 2050mm hot strip mill of Baosteel as an example, the roll wear magnitude and contour were calculated in theory, and measured by the present grinding machine in experiment. The calculated results agree well with the measured data in distribution, and also in general characteristics. Based on the calculated and measured results, an on-line prediction model by which the roll wear distribution characteristics of a CVC mill can be revealed more accurately was proposed. (author)

34

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

35

Sequential supervisory control, modelling and simulation of a multipass experimental rolling mill  

International Nuclear Information System (INIS)

This paper presents a Grafcet Model to control a laboratory-scale rolling mill and describes the design of a hybrid modelling and simulation strategy, its implementation in the G2 Real-time Expert System, and its application to the rolling mill. The rolling mill with its process variables and datalogging system is described. Grafcet is briefly overviewed, together with the implementation of the model on the rolling mill. The hybrid model base for the mill is designed from a combination of Object-Orientation, Rule-based Programming, GRAFCET, Equations, and procedures. The strategy, implemented in the real-time expert system, G2, involves the concurrent execution of three simulators: a continuous simulator, a GRAFCET simulator, and a heuristic simulator. (author)

36

Reliable roll force prediction in cold mill using multiple neural networks.  

Science.gov (United States)

The cold rolling mill process in steel works uses stands of rolls to flatten a strip to a desired thickness. The accurate prediction of roll force is essential for product quality. Currently, a suboptimal mathematical model is used. We trained two multilayer perceptrons, one to directly predict the roll force and the other to compute a corrective coefficient to be multiplied to the prediction made by the mathematical model. Both networks were shown to improve the accuracy by 30-50%. Combining the two networks and the mathematical model results in systems with an improved reliability. PMID:18255691

Cho, S; Cho, Y; Yoon, S

1997-01-01

37

INVESTIGATION OF THE MAINTENANCE ORGANISATION FOR HOT ROLLING MILLS  

Directory of Open Access Journals (Sweden)

Full Text Available

ENGLISH ABSTRACT: Production systems have undergone dramatic changes in recent years. Many companies have implemented new technologies such as flexible manufacturing systems. There is therefore a shift in focus to maintenance and the effective management thereof. Maintenance is a dynamic activity and is comprised of a large number of interacting variables. An effective maintenance organisation is required to control these variables .
This paper discusses the building of a maintenance organisation and the aspects that should be considered during the design. The way in which five companies that operate hot rolling mills apptoached the problem of building an effective maintenance organisation was investigated.

AFRIKAANSE OPSOMMING: y eryaardigingstelsels het drastiese veranderinge ondergaan die afgelope aantal jaar. Verskeie Il1~atskappyemaak nou gebruik van nuwe tegnologiee, soas byvoorbeeld aanpasbare vervaardigingstelsels. Daar is gevolglik 'n verskuiwing in fokus na instandhouding en die effektiewe bestuur daarvan. lnstandhouding is 'n dinamiese aktiwiteit en behels 'n groot aantal ' gekoppelde veranderlikes. 'n Effektiewe instandhoudingsorganisasie word benodig om hierdie v'eranderlikes te beheer.
Hierdie artikel bespreek die daarstelling van die instandhoudingsorganisasie en die parameters V~toorweeg moet word tydens die ontwerp. Die wyse waarop vyf maatskappye wat }V~rIl1walse bedryf die ontwikkeling van 'neffektiewe organisasie vir instandhouding benader hc(is ondersoek .

P.K. Pretorius

2012-01-01

38

A small economical rolling mill for producing foils used as nuclear targets  

International Nuclear Information System (INIS)

A small, economical rolling mill has found extensive use in the Physics Division Target Development Laboratory for producing foils used in atomic and nuclear physics experiments. This apparatus is quite versatile for its size and enables a large fraction of our target foil requirements to be realized in-house. A description of the rolling mill and some examples of targets produced will be given

39

Rolling process simulation of a pair-crossed hot strip mill  

Energy Technology Data Exchange (ETDEWEB)

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

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

2000-07-01

40

Coupled dynamic modeling of rolls model and metal model for four high mill based on strip crown control  

Science.gov (United States)

The crown is a key quality index of strip and plate, the rolling mill system is a complex nonlinear system, the strip qualities are directly affected by the dynamic characteristics of the rolling mil. At present, the studies about the dynamic modeling of the rolling mill system mainly focus on the dynamic simulation for the strip thickness control system, the dynamic characteristics of the strip along the width direction and that of the rolls along axial direction are not considered. In order to study the dynamic changes of strip crown in the rolling process, the dynamic simulation model based on strip crown control is established. The work roll and backup roll are considered as elastic continuous bodies and the work roll and backup roll are joined by a Winkler elastic layer. The rolls are considered as double freely supported beams. The change rate of roll gap is taken into consideration in the metal deformation, based on the principle of dynamic conservation of material flow, the two dimensional dynamic model of metal is established. The model of metal deformation provides exciting force for the rolls dynamic model, and the rolls dynamic model and metal deformation model couple together. Then, based on the two models, the dynamic model of rolling mill system based on strip crown control is established. The Newmark-? method is used to solve the problem, and the dynamic changes of these parameters are obtained as follows: (1) The bending of work roll and backup roll changes with time; (2) The strip crown changes with time; (3) The distribution of rolling force changes with time. Take some cold tandem rolling mill as subject investigated, simulation results and the comparisons with experimental results show that the dynamic model built is rational and correct. The proposed research provides effective theory for optimization of device and technological parameters and development of new technology, plays an important role to improve the strip control precision and strip shape quality.

Sun, Jianliang; Peng, Yan; Liu, Hongmin

2013-01-01

 
 
 
 
41

Simulation of the thermal conditions of rolls in a wide-strip hot-rolling mill to determine their effective cooling conditions  

Science.gov (United States)

An advanced procedure is developed for the thermal calculation of the rolls in a wide-strip hot-rolling mill (WSHRM). It combines the following two adaptive models: the thermal balance in the active surface layer in a roll per revolution and the thermal balance in the main zones of work and backup rolls with axisymmetric temperature fields with allowance for the heat exchange between a strip, rolls, the coolant, and the environment. In contrast to the well-known models, this advanced procedure calculates the bulk mean temperature and the thermal profile in a roll more accurately, since the temperature drop across the surface layer in this procedure is calculated allowing for the intensities of the contact and convective heat exchange between rolls. Data on the coefficient of heat transfer from rolls to the coolant supplied at an excess pressure of 1.0-1.5 MPa are presented for the first time. This procedure is used in a 2000 WSHRM and improves the transverse profile of hot-rolled strips due to a stabilized thermal profile in rolls.

Garber, E. A.; Khlopotin, M. V.; Traino, A. I.; Popov, E. S.; Savinykh, A. F.

2009-06-01

42

Regulation of the Heating Furnace in Tube Rolling Mill  

Directory of Open Access Journals (Sweden)

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

Kostúr, K.

2006-01-01

43

In-line material characterization measurements in high speed rod rolling mills  

International Nuclear Information System (INIS)

The ability to provide reliable and timely feedback on the performance of the thermomechanical process in a rolling mill is becoming more important as rolling speeds continue to increase. With rolling speeds now exceeding 120 m/s and production rates exceeding 100 t/h on single strand mills, rapid measurement of the finished product is required to evaluate the process before much unacceptable product is rolled. Conventional means of sample taking, specimen preparation and testing are not only labor-intensive, but also result in relatively slow feedback to the process operators. This paper describes the application of surface volume imaging technology to on-line measurement of pertinent material properties of steel rod. The system examines the microstructural features of the product, such as grain size, crystallographic texture and phase distribution, and correlates those features with mechanical properties such as tensile strength. Furthermore, surface characteristics of the oxide layer can be evaluated and quantified. (author)

44

Evaluation of the fatigue damage of rolls for strip mills below the surface by x-ray diffraction method  

International Nuclear Information System (INIS)

Technique of the X-ray diffraction line profile analysis has been applied to the study of fatigue damage below the surface of the work and the backup rolls of cold strip mill and the backup rolls of hot strip mill. Half value breadth has been taken as a measure of fatiguing. Fatigued zone below the surface of rolls is well correlated with the half contact length of roll, L; 0.03 L in the work roll of cold strip mill and 0.1 L in the other rolls. Changes in the half value breadth with increase in cycles of roll contact differ in accordance with the surface hardness of the rolls: continued cycling results in decrease of the half value breadth at surface in hard rolls (H sub(s) >= 60) and increase in soft rolls (H sub(s) <= 50). The technique of X-ray study of fatigue can be extended to prediction and prevention of accidental failure of rolls due to fatigue fracture such as spalling. Furthermore the amount of surface dressing at regular maintenance of rolls can be saved significantly on the basis of accurate evaluation of the depth of fatigue damaged zone. (author)

45

Determination of scrap in rolling mills using radionuclides  

International Nuclear Information System (INIS)

Metal flow in an ingot can be studied during forming by a radiometric method. A Fe and 60Co radioactive sample is placed into an opening in the ingot and the sample position in the metal being formed is determined using a scintillation detector. The labelling of decisive points on the ingot heel with radionuclides and their identification in the semifinished product after rolling are advantageous for determining the effect of the ingot weight on the amount of technological scrap with respect to the action of the decisive geometric factors of metal deformation. THe absolute amount of scrap increases parabollically with the ingot cross section. (M.S.)

46

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

International Nuclear Information System (INIS)

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

47

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

Science.gov (United States)

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

Moussaoui, A. K.; Abbassi, H. A.; Bouazza, S.

2008-06-01

48

Optimal Design of Flatness Control of Six High Single-Stand Cold Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available The key control model for cold rolling, i.e., the so-called flatness control systems for six high cold rolling mill is investigated deeply and a kind of optimal design is obtained. The overall flatness control system consists of the sub-system of flatness signal processing and the sub-system of flatness optimum control. Indeed, several compensation models are included in the sub-system of flatness signal processing for releasing detecting errors, and optimal control outputs, such as skewing roll and bending roll, are calculated easily by the underlying flatness optimum control systems. All the above functional models are simulated by using the Matlab simulation software, and the effectiveness and optimum of the proposed approaches are illustrated.

Xiangpeng XIE

2014-03-01

49

Strip/Foil Rolling Mill Stochastic Excitation Model and Its Stability  

Directory of Open Access Journals (Sweden)

Full Text Available Based on the stochastic rolling force data from aluminum hot strip tandem mill, the ARMA time series model and the stochastic excitation power spectral density (PSD model are established, and the stochastic rolling forces excitation model is established by utilizing Levenberg-Marquardt combined with generalized global planning algorithm. A two dimensional stochastic nonlinear dynamical model of rolls is presented considering the stochastic factor of the rolling force. The Hamilton function is also described as one dimension diffusion process by using stochastic average method, the singular boundary theory was taken for analyzing the global stochastic stability of the system, and the system’s stochastic stability was researched by solving the Fokker-Planck-Kolmogorov (FPK equation. The results show that the stochastic excitation model obtained has significance for analyzing and researching stochastic dynamics characteristics to the system, and also generalized energy H in the range of 0.02 to 0.4, the system’s response has the minimum transition probability density, and the system state is not easy to change, therefore the system generalized energy H should be to limit in this range in the design and operation of the rolling mill.

Baoyu Xu

2012-06-01

50

Soft Starting Arrangements Availables for Hot Rolling Mills for Energy Conservation  

Science.gov (United States)

The conventional rolling mills in India are producing a major part of structural steel requirement of the country. The energy conservation in these rolling mills can be achieved mainly by reducing the size of the prime mover i.e. main electric motor. The power consumption per ton can be considerably decreased through proper selection of electric motor since it has been an observation by many surveyors[1] that the selection of electric motor of the rolling mill has been almost five to ten times on the higher side which can be easily verified from the power consumption and motor working data.Flywheel is a mechanical storage device. Largest size of flywheels are frequently recommended for smooth running of rolling mills. The main difficulty encountered in selecting large capacity flywheel or flywheel gear box system is the starting of the mill with smaller capacity electric motor. The starting characteristic of electric motor is not suitable for starting such rolling mill with very high inertia flywheel. In such condition it becomes very essential to introduce the soft starting arrangement for the electric motor so that considerably small size motor can start the flywheel effectively.Soft starters are used for the smooth start-up control of three-phase induction motors. The soft starter is functionally located between the Flywheel and the electric motor. In selecting the correct soft starter to suit the application the peculiarities of the soft start should be considered. In the prevailing conditions we use the motor of high horse power due to the fact that the flywheel requires high torque to be driven initially. For the same reason the efficiency of the flywheel is very low initially. Once the flywheel stores sufficient power which is required at the start up, the flywheel then requires less power than given initially. If we somehow are able to increase the efficiency of the flywheel using a flexible electrical, mechanical, hydraulic or flexible drives with different combinations (Electrical, Mechanical, Hydraulic) then the motor of less horse power can thus be installed to run the flywheel.This paper gives an idea of available type of the soft starting arrangement for a rolling mill so that horse power of motor can be reduced without affecting the working of the mill. Hence optimum selection of the soft starting arrangement is to be done so that initial and billing cost will be less.

Bisen, A. M.; Bapat, P. M.; Gagnuly, S. K.

2012-07-01

51

Balance mathematical model for the heat regime of cold rolling of electrical steel strips in a reversing mill  

Science.gov (United States)

A mathematical model is developed to describe the heat regime of a reversing cold-rolling mill that takes into account the substantial differences between the heat processes occurring in reversing and continuous mills. Model and heat balance equations are used to calculate the strip temperature in passes and the temperature and the heat profile of rolls as functions of the rolling regime parameters and the heat-transfer coefficients that characterize the heat exchange between a strip, rolls, and lubricant-cooling agents and depend on the cooling system parameters of a mill. The model can be used to find a heat regime favorable for achieving the required final magnetic properties of electrical steel. The efficiency of the factors affecting the heat regime in rolling is studied.

Garber, E. A.; Aleshin, A. E.; Degtev, S. S.; Traino, A. I.

2013-11-01

52

Preparation Model Based Control System For Hot Steel Strip Rolling Mill Stands  

Science.gov (United States)

As part of a research project on El-hadjar Hot Steel Rolling Mill Plant Annaba Algeria a new Model based control system is suggested to improve the performance of the hot strip rolling mill process. In this paper off-line model based controllers and a process simulator are described. The process models are based on the laws of physics. these models can predict the future behavior and the stability of the controlled process very reliably. The control scheme consists of a control algorithm. This Model based Control system is evaluated on a simulation model that represents accurately the dynamic of the process. Finally the usefulness to the Steel Industry of the suggested method is highlighted.

Bouazza, S. E.; Abbassi, H. A.; Moussaoui, A. K.

2008-06-01

53

Kinetic study of the removal of Cu(II) from aqueous solutions by rolling mill scale  

International Nuclear Information System (INIS)

The removal of Cu(II) from aqueous solutions by rolling mil scale occurs through a process of oxidation-reduction or cementation of Cu''2+ ions in aqueous solution onto metallic iron (Fe''0) contained in the mill scale. The kinetics of cementation of copper onto iron was evaluated over different temperatures, initial copper concentrations and solid/liquid relations. Process of copper removal by rolling mill scale obeys a first-order kinetic law. The rate constant value (k) varies with temperature and initial cation concentration in solution at low temperatures. At high temperatures the value of k remains practically constant. the solid/liquid relation value affects the rate constant value too. (Author) 19 refs

54

[Effect of working conditions on myocardial contractility in tube-rolling mill workers].  

Science.gov (United States)

Tetrapolar rheography, M-echocardiography and visual searching ++Doppler echocardiography were used to study the state of the myocardium in 228 practically healthy male workers engaged in different working conditions at a tube-rolling mill. Revealed were increased myocardium and myocardium contraction disorders resulting from physical over-load in combination with heating microclimate and noise. The contributors proposed approaches to the preclinical diagnosis of such changes, which could be applied to the elaboration of preventive measures. PMID:1831780

Miller, M B

1991-01-01

55

A nucleonic thickness control system for a thin sheet rolling mills machine  

International Nuclear Information System (INIS)

A nuclear transmission thickness gauge and control system was developed. It was used to improve the thickness control of the thin sheet metal production in the cold rolling mills. The deviation from the nominal thickness of the sheet metal was reduced through automatic correction in continuous production process. The five main parts of the nuclear thickness gauge are : radiation source. radiation detection system, analog to digital converter, micro controller and interfaces. A thickness gauge with Am-241 of 3.7 x 109 Bq as radiation source together with a 1 x 1 inch NaI(T 1) as radiation detector was installed on an old version cold rolling mills producing brass sheets of various thickness from 0.1 to 0.5 mm with a feeding speed of 25 m/min. It was found that with nuclear thickness gauge the brass sheet thickness could be controlled with a deviation of ±0.01 mm in comparison with ±0.02 mm resulting from the previous conventional thickness control. Thus, the performance of the old version cold rolling mills can be improved through the development of an automatic nuclear electronic thickness gauging

56

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

57

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

Directory of Open Access Journals (Sweden)

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

A. Gryc

2014-10-01

58

Simulation of the longitudinal thickness deviation of the steel strips hot rolled in the continuous group of a broad-strip mill  

Science.gov (United States)

A model for the formation of longitudinal thickness deviation in hot-rolled strips as a function of the rolling parameters and an algorithm for optimizing the rolling conditions for the criterion of the minimum longitudinal thickness deviation are developed and implemented in the form of computer programs. This optimization is performed by the redistribution of percent reductions over the stands of the finishing group in a broad-strip hot-rolling mill. As a result of the application and industrial tests of the developed computer programs on a 2000 rolling mill, the longitudinal thickness deviation of hot-rolled strips is decreased by a factor of 1.87.

Garber, E. A.; Pospelov, I. D.; Traino, A. I.; Savinykh, A. F.; Nikolaev, N. Yu.; Mishnev, P. A.

2012-09-01

59

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

60

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

International Nuclear Information System (INIS)

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

 
 
 
 
61

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

62

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

63

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

International Nuclear Information System (INIS)

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

64

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 equipmen...

Vijay Gautam

2013-01-01

65

Understanding Rolle's Theorem  

Directory of Open Access Journals (Sweden)

Full Text Available This paper reports on an experiment studying twelfth grade students’ understanding of Rolle’s Theorem. In particular, we study the influence of different concept images that students employ when solving reasoning tasks related to Rolle’s Theorem. We argue that students’ “container schema” and “motion schema” allow for rich concept images.

REVATHY PARAMESWARAN

2009-01-01

66

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

67

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

International Nuclear Information System (INIS)

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

68

Work during screw rolling  

Science.gov (United States)

A new technique is proposed to determine the specific volume work of deformation during screw rolling. Methods for determining the work of deformation in various sections of the deformation zone in a piercing mill are considered. The dependence of the work of deformation on the reduction in the deformation zone is obtained. A new approach is proposed to calculate the fracture sensitivity and the working of the structure of continuously cast round billets. The effect of the reduction ratio on the work of deformation in similar piercing mills located at OAO Pervoural'sk Nonvotrubnyi Plant and the Yuzhnotrubnyi Plant is estimated.

Golubchik, R. M.; Merkulov, D. V.; Klempert, E. D.; Medvedev, E. K.; Shelest, A. E.

2011-05-01

69

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

Scientific Electronic Library Online (English)

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

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

70

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

International Nuclear Information System (INIS)

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

71

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

72

Rheology of coal-water slurries prepared by the HP roll mill grinding of coal. Quarterly technical progress report No. 10, December 1, 1994--February 28, 1995  

Energy Technology Data Exchange (ETDEWEB)

The research during this quarter was, directed towards: (1) systematic study of preparation of coal fines by high-pressure roll mill grinding and by high-pressure roll mill/ball mill hybrid grinding, (2) investigation of the rheological behavior of slurries prepared with fines produced by these techniques, and (3) study of the effect of coal cleaning on both short term and long term slurry rheology. Results are discussed.

Fuerstenau, D.W.

1995-03-01

73

Rolling of rods of tungsten alloyed with lanthanum  

International Nuclear Information System (INIS)

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

74

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

75

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

Scientific Electronic Library Online (English)

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

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

2013-03-01

76

Rolling friction and bistability of rolling motion  

CERN Document Server

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

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

2005-01-01

77

The Physical Flow of Materials and the Associated Costs in the Production Process of a Rolling Mill  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Efficiency of resources use is, in a large extent, determined by the organization of production flow and the way of their control. The optimization of materials flow in the production process requires the identification of physical flows of goods and it cost. In the article the physical flow process of materials stream in the production process in one of Polish rolling mill and also its logistics analysis and cost analysis are presented.

Holisz-burzyn?ska, J.; Staniewska, E.; Budzik, R.

2007-01-01

78

The Physical Flow of Materials and the Associated Costs in the Production Process of a Rolling Mill  

Directory of Open Access Journals (Sweden)

Full Text Available Efficiency of resources use is, in a large extent, determined by the organization of production flow and the way of their control. The optimization of materials flow in the production process requires the identification of physical flows of goods and it cost. In the article the physical flow process of materials stream in the production process in one of Polish rolling mill and also its logistics analysis and cost analysis are presented.

Holisz-Burzy?ska, J.

2007-01-01

79

Occupational noise exposure and sensorineural hearing loss among workers of a steel rolling mill.  

Science.gov (United States)

Hearing loss is one of the most common chronic health conditions and has important implications for the patient's quality of life. However, hearing loss is substantially underestimated and under treated. The purpose of this study was to determine the prevalence of sensorineural hearing loss among the workers in a steel rolling mill in Nigeria. Each of the 150 randomly selected subjects had a structured questionnaire administered to them, followed by a full otological examination. Of these, 116 had tympanometry and pure-tone audiometry. Also a noise mapping of their respective work units was done. The workers were exposed to noise levels varying from 49 to 93 dBA. About 28.2% of the 103 who had their audiogram analysed had mild to moderate sensorineural hearing loss in their better ear and 56.8% of them had mild to moderate sensorineural hearing loss in their worse ear. The pure-tone average and the average hearing thresholds at 4 kHz for the groups significantly increased with an increasing noise exposure level. The prevalence of sensorineural hearing loss among the study population is high; and noise exposure is at least contributory. Pre-employment and regular audiometry while on the job is highly recommended. PMID:16680467

Ologe, Foluwasayo E; Akande, Tanimola M; Olajide, Toye G

2006-07-01

80

Synchronous control for the hydraulic width system of edger rolling mill  

Science.gov (United States)

Edger rolling mill is a load system in which the upper and the lower cylinder actuate a side vertical roller at the same time. Due to the linkage of the load, the output and control of two channels influence each other. Synchronic-control issue is discussed aim to the system with serious coupling. Neural network inverse as decoupling controller is proposed to account for the complicated process dynamics characterized by nonlinear, time-varying, uncertain and load couple properties. Firstly, the reversibility of the system is analyzed and the ANN inverse dynamic is constructed based on a feed forward and neural network structure with enlarged back propagation algorithm. Secondly, the system is changed into two pseudo-linear sub-system through connecting the controlled system and inverse dynamic model in series. Aim to two pseudo-linear sub-system pole assignments method is proposed to enhance the whole system performance. A series simulation was conducted and results showed the proposed controller does better than traditional PID not only on decoupling but also on the transient response, as well as robustness under vary conditions.

Ning, Shurong; Fan, Zhuoyu

2008-10-01

 
 
 
 
81

Finger milling-cutter CNC generating hypoid pinion tooth surfaces based on modified-roll method and machining simulation  

Science.gov (United States)

The two coordinate systems of cradle-type hypoid generator and free-form CNC machine tool by application disc milling-cutter to generate hypoid pinion tooth surfaces based on the modified-roll method were set up, respectively, and transformation principle and method for machine-tool settings between the two coordinate systems was studied. It was presented that finger milling-cutter was mounted on imagined disc milling-cutter and its motion was controlled directly by CNC shafts to replace disc milling-cutter blades effective cutting motion. Finger milling-cutter generation accomplished by ordered circular interpolation was determined, and interpolation center, starting and ending were worked out. Finally, a hypoid pinion was virtually machined by using CNC machining simulation software VERICUT.

Li, Genggeng; Deng, Xiaozhong; Wei, Bingyang; Lei, Baozhen

2011-05-01

82

Grain refinement of magnesium alloy sheets by ARB using high-speed rolling mill  

Science.gov (United States)

Applications of ARB to magnesium alloys were limited due to low deformability. The authors recently found that the rollability of the alloys is significantly improved in highspeed rolling. It is supposed that the severe plastic deformation of magnesium alloy sheets is feasible if rolling in ARB processes is conducted at high speed. In this study, AZ31B and ZK60A sheets are processed by ARB up to five cycles at 423K with a speed of 1000m/min. Vickers hardness increases with increasing number of ARB cycles, while the tensile strength shows the maximum after the second cycle. The grain size is reduced significantly at the first cycle and decreases gradually from the second cycle. The mean grain sizes after five cycles are 1.6?m for AZ31B and 1.8?m for ZK60A. It is concluded that ARB using high-speed rolling is effective for grain refinement of magnesium alloys.

Utsunomiya, Hiroshi; Izumi, Ken-ichi; Sakai, Tetsuo; Mukai, Toshiji

2009-05-01

83

Grain refinement of magnesium alloy sheets by ARB using high-speed rolling mill  

International Nuclear Information System (INIS)

Applications of ARB to magnesium alloys were limited due to low deformability. The authors recently found that the rollability of the alloys is significantly improved in highspeed rolling. It is supposed that the severe plastic deformation of magnesium alloy sheets is feasible if rolling in ARB processes is conducted at high speed. In this study, AZ31B and ZK60A sheets are processed by ARB up to five cycles at 423K with a speed of 1000m/min. Vickers hardness increases with increasing number of ARB cycles, while the tensile strength shows the maximum after the second cycle. The grain size is reduced significantly at the first cycle and decreases gradually from the second cycle. The mean grain sizes after five cycles are 1.6?m for AZ31B and 1.8?m for ZK60A. It is concluded that ARB using high-speed rolling is effective for grain refinement of magnesium alloys.

84

Genetic based sensorless hybrid intelligent controller for strip loop formation control between inter-stands in hot steel rolling mills.  

Science.gov (United States)

Safe operating environment is essential for all complex industrial processes. The safety issues in steel rolling mill when the hot strip passes through consecutive mill stands have been considered in this paper. Formation of sag in strip is a common problem in the rolling process. The excessive sag can lead to scrap runs and damage to machinery. Conventional controllers for mill actuation system are based on a rolling model. The factors like rise in temperature, aging, wear and tear are not taken into account while designing a conventional controller. Therefore, the conventional controller cannot yield a requisite controlled output. In this paper, a new Genetic-neuro-fuzzy hybrid controller without tension sensor has been proposed to optimize the quantum of excessive sag and reduce it. The performance of the proposed controller has been compared with the performance of fuzzy logic controller, Neuro-fuzzy controller and conventional controller with the help of data collected from the plant. The simulation results depict that the proposed controller has superior performance than the other controllers. PMID:18093589

Thangavel, S; Palanisamy, V; Duraiswamy, K

2008-04-01

85

Recent trends for rolling equipment  

Energy Technology Data Exchange (ETDEWEB)

Facility investments in the steel industry have increased considerably in the last two to three years. This is especially true for equipment related to the so-called high added-value steels'' such as rolling mills for automotive strip, surface treatment lines, continuous annealing lines, continuous pickling lines, et al. New technologies developed for these equipment have done much to accelerate trends toward higher quality, higher efficiency, increased automation, and increased yield. These new technologies include; application of mills to materials for the electronic industry, to annealing and galvanizing process lines for automotive sheets; fully continuous cold rolling mills; old mills rebuilt to state-of-the-art specifications; new process line technology, including a way to obtain a consistent coating thickness on hot-dip galvanizing lines, special bearings for rolls submerged in zinc pots, and a new scale removal device; moreover, AC variable-speed devices; advanced controllers; automation of peripherals; and automation of sample preparation and testing. These important new trends in rolling mill equipment technology are outlined with the definite name of equipment. 3 refs., 2 figs., 3 tabs.

Fujino, N.; Sugiyama, T.; Shimizu, I. (Hitachi, Ltd., Tokyo (Japan))

1990-08-01

86

Adaptation of an Asperity Ploughing Model to Measured Roll Topographies  

Science.gov (United States)

A previously published asperity ploughing model has been adapted in order to approximate the measured as-ground roll surface topography. The model is then integrated with classical cold rolling plastic deformation equations including coupling to the lubricant film evolution through the roll bite. The friction distribution through the roll bite is thus a function of the specific details of the roll surface topography as well as the process parameters. predictions of roll force, torque and forward slip as well as sliding distance and volume of metal swept out by the asperities are then made and compared to experimental measurements for an aluminum alloy rolled on a laboratory rolling mill.

Lalli, L. A.; Malkani, H. G.; Sheu, S.

2004-06-01

87

Online Prediction Under Model Uncertainty via Dynamic Model Averaging: Application to a Cold Rolling Mill.  

Science.gov (United States)

We consider the problem of online prediction when it is uncertain what the best prediction model to use is. We develop a method called Dynamic Model Averaging (DMA) in which a state space model for the parameters of each model is combined with a Markov chain model for the correct model. This allows the "correct" model to vary over time. The state space and Markov chain models are both specified in terms of forgetting, leading to a highly parsimonious representation. As a special case, when the model and parameters do not change, DMA is a recursive implementation of standard Bayesian model averaging, which we call recursive model averaging. The method is applied to the problem of predicting the output strip thickness for a cold rolling mill, where the output is measured with a time delay. We found that when only a small number of physically motivated models were considered and one was clearly best, the method quickly converged to the best model, and the cost of model uncertainty was small; indeed DMA performed slightly better than the best physical model. When model uncertainty and the number of models considered were large, our method ensured that the penalty for model uncertainty was small. At the beginning of the process, when control is most difficult, we found that DMA over a large model space led to better predictions than the single best performing physically motivated model. We also applied the method to several simulated examples, and found that it recovered both constant and time-varying regression parameters and model specifications quite well. PMID:20607102

Raftery, Adrian E; Kárný, Miroslav; Ettler, Pavel

2010-02-01

88

Parametric Roll Instability of Ships  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Sheikh, Irfan Ahmad

2008-01-01

89

Thermomechanical Behavior of Work Rolls During Warm Strip Rolling  

Science.gov (United States)

A mathematical model was developed to assess thermomechanical behavior of work rolls during warm rolling processes. A combined finite element analysis-slab method was first developed to determine thermal and mechanical responses of the strip being rolled under steady-state conditions, and then, the calculated roll pressure and temperature field were utilized as the governing boundary conditions for the thermomechanical problem of the work roll. Finally, the thermomechanical stresses within the work rolls were predicted by a thermoelastic finite element approach. The results of the model indicate that, in warm strip rolling, thermal and mechanical stresses developed in the work rolls are comparable, and thus, both thermal and mechanical aspects of the problem should be considered in such a problem. Besides, the model was shown to be capable of determining the effects of various rolling parameters on the thermomechanical behavior of the work rolls during warm rolling process.

Khalili, L.; Serajzadeh, S.; Koohbor, B.

2012-12-01

90

Finite element analysis of edge fracture of electrical steel strip in reversible cold rolling mill  

Energy Technology Data Exchange (ETDEWEB)

An electrical steel strip is commonly used as a core material in all types of electric transformers and motors. It is produced by a cold rolling process. In this paper, a damage mechanics based approach that predicts the edge fracture of an electrical steel strip during cold rolling is presented. We adopted the normal tensile stress criterion and the fracture energy method as a damage initiation criterion and a damage evolution scheme, respectively. We employed finite element analysis (FEA) to simulate crack initiation and propagation at the initial notch located at the edges of the strip. The material constants required in FEA were experimentally obtained by tensile tests using a standard and a notched sheet type specimen. The results reveal that the edge crack was initiated at the entrance of the roll bite and that it rapidly evolved at the exit. The evolution length of the edge crack increased as the length of the initial notch as well as front tension reel force of the strip increased.

Byon, Sang Min [Dong A Univ., Busan (Korea, Republic of)

2012-12-15

91

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.

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

92

Finite element analysis of edge fracture of electrical steel strip in reversible cold rolling mill  

International Nuclear Information System (INIS)

An electrical steel strip is commonly used as a core material in all types of electric transformers and motors. It is produced by a cold rolling process. In this paper, a damage mechanics based approach that predicts the edge fracture of an electrical steel strip during cold rolling is presented. We adopted the normal tensile stress criterion and the fracture energy method as a damage initiation criterion and a damage evolution scheme, respectively. We employed finite element analysis (FEA) to simulate crack initiation and propagation at the initial notch located at the edges of the strip. The material constants required in FEA were experimentally obtained by tensile tests using a standard and a notched sheet type specimen. The results reveal that the edge crack was initiated at the entrance of the roll bite and that it rapidly evolved at the exit. The evolution length of the edge crack increased as the length of the initial notch as well as front tension reel force of the strip increased

93

Grain refinement of magnesium alloy sheets by ARB using high-speed rolling mill  

Energy Technology Data Exchange (ETDEWEB)

Applications of ARB to magnesium alloys were limited due to low deformability. The authors recently found that the rollability of the alloys is significantly improved in highspeed rolling. It is supposed that the severe plastic deformation of magnesium alloy sheets is feasible if rolling in ARB processes is conducted at high speed. In this study, AZ31B and ZK60A sheets are processed by ARB up to five cycles at 423K with a speed of 1000m/min. Vickers hardness increases with increasing number of ARB cycles, while the tensile strength shows the maximum after the second cycle. The grain size is reduced significantly at the first cycle and decreases gradually from the second cycle. The mean grain sizes after five cycles are 1.6{mu}m for AZ31B and 1.8{mu}m for ZK60A. It is concluded that ARB using high-speed rolling is effective for grain refinement of magnesium alloys.

Utsunomiya, Hiroshi; Izumi, Ken-ichi; Sakai, Tetsuo [Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Mukai, Toshiji [Structural Metals Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)], E-mail: uts@mat.eng.osaka-u.ac.jp

2009-05-01

94

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

International Nuclear Information System (INIS)

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

95

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

96

7.SP Rolling Dice  

Science.gov (United States)

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

97

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

98

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

99

Spray Rolling Aluminum Strip for Transportation Applications  

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-02-01

100

Radiometric study of creep in ingot rolling  

International Nuclear Information System (INIS)

The radiometric study of creep during ingot rolling performed in the rolling mill of the Vitkovice Iron and Steel Works and the first results are described. Selected sites in 3 to 8 ton ingots were labelled with 2 to 3.7x105 Bq of 60Co and after rolling into blocks, the transposition of the labelled sites of the ingots was investigated. The results indicate creep during rolling, local extension in certain sites under study and help to determine the inevitable bottom crop incurred in the forming. Finally, the requirements put on the radiometric apparatus for the next stages of technological research are presented. (author)

 
 
 
 
101

Grooved roll for a high speed twin roll caster  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: Purpose of this paper is investigation of the effect of roll-surface on the strip-surface. Improvement ofsmall cracks on the strip-surface was tried and effect of groove at the roll surface on the strip surface was shown.Design/methodology/approach: Method used in the present study was high speed twin roll caster withgrooved roll. Two kinds of grooves were used: one was parallel groove and the other was cross groove machinedby knurling and bite attached to a lathe.Findings: Findings of this research are that grooved roll was effective to eliminate the small cracks on the stripsurface. The contact condition between the roll and the melt became uniform by the small groove on the rollsurface. Contact area became small, and heat transfer between the melt and roll became small, too. As the result,chill structure did not become columnar, and crack did not occur. Groove pattern on the strip surface could beerased by the cold rolling.Research limitations/implications: Research limitation is that groove life could not be investigated.Practical implications: Practical implications are as below. The roll load was small and strip was not hot-rolledin a high speed twin roll caster. The grooved roll made strip-surface sound. Grooved 600mm width roll was tested,and usefulness of the grooved roll was shown.Originality/value: In the present study effect of the grooved roll on a high speed twin roll caster was investigated.

T. Haga

2008-04-01

102

Rolling Shutter Stereo  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A huge fraction of cameras used nowadays is based on CMOS sensors with a rolling shutter that exposes the image line by line. For dynamic scenes/cameras this introduces undesired effects like stretch, shear and wobble. It has been shown earlier that rotational shake induced rolling shutter effects in hand-held cell phone capture can be compensated based on an estimate of the camera rotation. In contrast, we analyse the case of significant camera motion, e.g. where a by...

Saurer, O.; Ko?ser, Kevin; Bouguet, J. -y; Pollefeys, M.

2013-01-01

103

Pilot-industrial technology of sintered tungsten bar section rolling  

International Nuclear Information System (INIS)

Results of development and industrial introduction of new technology for rolling of bar sections from sintered tungsten on specialized rolling mill MK-380 with four-high passes of the Chelyabinsk Polytechnical Institute design are given. The rolling mill design is described and recommendations are given as to the working roll materials. The new technology is characterized by a higher output and quality of produced sections in comparison with existing methods of processing

104

Spray Rolling Aluminum Strip  

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-05-10

105

A New Method of Manufacturing Small-Diameter Bars and Tubes from Hardly Deformable Steels in Skew Rolling  

Directory of Open Access Journals (Sweden)

Full Text Available The paper discusses the process of hot rolling on skew rolling mills and compares it with other methods of manufacturing rods (shape milling and tubes (pilger rolling. The method and results of calculation of the optimal price of a three-roll skew rolling mill taking into account the benefits for the purchaser and the manufacturer are given.

Ga?kin, A. M.

2007-01-01

106

Maintenance strategy for tilting table of rolling mill based on reliability considerations  

International Nuclear Information System (INIS)

Reliability centred maintenance (RCM) is a new strategic framework for ensuring that any asset continues to perform, as its users want it to perform. RCM is a process used to determine the maintenance requirement of any physical asset in its operating context. RCM process entails asking seven questions about each of the selected assets. It makes use of two documents namely, RCM information worksheet and RCM decision worksheet. RCM decision diagram integrates all the decision processes into a single strategic framework. RCM concept developed by US commercial airlines industry has been successfully implemented by Military, Navy, Nuclear power plants, electric power generation and distribution undertakings and several other sectors. These projects have been carried out in the United Kingdom, The Republic of Ireland, the United States, Hong Kong, Australia, Spain and Singapore. The fact that people has enthusiastically received RCM at all levels and has enabled users to achieve some remarkable successes in all of these countries, suggests that it can be universally employed. Literature review indicates that RCM approach is not conventionally applied in process industries in India. Presently, predictive maintenance (PDM) approach along with conventional preventive maintenance is used in continuous/process industries. This approach if implemented in totality will increase the production cost to a large degree and make the production uneconomical. Similarly breakdown maintenance (BDM) approach cannot be applied in such industries as each breakdown involves huge costs. RCM approach is a compromise between PDM and BDM approach for optimising the cost and ensuring the availability of machine. The RCM approach has been applied to the tilting table system of rolling mill for the research work reported in this paper. In the present study, preventive maintenance tasks suggested for power transmission subsystem, guiding and transportation subsystem and hydraulic subsystem in tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices

107

Maintenance strategy for tilting table of rolling mill based on reliability considerations  

Energy Technology Data Exchange (ETDEWEB)

Reliability centred maintenance (RCM) is a new strategic framework for ensuring that any asset continues to perform, as its users want it to perform. RCM is a process used to determine the maintenance requirement of any physical asset in its operating context. RCM process entails asking seven questions about each of the selected assets. It makes use of two documents namely, RCM information worksheet and RCM decision worksheet. RCM decision diagram integrates all the decision processes into a single strategic framework. RCM concept developed by US commercial airlines industry has been successfully implemented by Military, Navy, Nuclear power plants, electric power generation and distribution undertakings and several other sectors. These projects have been carried out in the United Kingdom, The Republic of Ireland, the United States, Hong Kong, Australia, Spain and Singapore. The fact that people has enthusiastically received RCM at all levels and has enabled users to achieve some remarkable successes in all of these countries, suggests that it can be universally employed. Literature review indicates that RCM approach is not conventionally applied in process industries in India. Presently, predictive maintenance (PDM) approach along with conventional preventive maintenance is used in continuous/process industries. This approach if implemented in totality will increase the production cost to a large degree and make the production uneconomical. Similarly breakdown maintenance (BDM) approach cannot be applied in such industries as each breakdown involves huge costs. RCM approach is a compromise between PDM and BDM approach for optimising the cost and ensuring the availability of machine. The RCM approach has been applied to the tilting table system of rolling mill for the research work reported in this paper. In the present study, preventive maintenance tasks suggested for power transmission subsystem, guiding and transportation subsystem and hydraulic subsystem in tilting tables are 14 scheduled on-condition tasks, 10 scheduled on-restoration tasks, seven scheduled discard task. Whereas for 14 failure modes no scheduled maintenance has been proposed. Existing maintenance schedule for tilting tables indicates the maintenance action as and when required. Hence RCM based schedule specifies that additional preventive maintenance tasks need to be executed as compared to none initially. Cost incurred for this can be offset from the savings accrued from reduction in loss of production due to repetitive breakdowns. The methodology of RCM adopted in western industries cannot be applied as it is to Indian industries because of labour oriented nature, partially computerised information systems, non-availability of the information about cost of loss of production due to breakdown and age-reliability pattern of equipment, insufficient maintenance database. These problems can be overcome by development of sound MMIS, formulation of RCM review group and imparting suitable training to acquire the relevant skills in RCM. Thus RCM methodology can be applied to Indian industry for reduction of breakdowns as well as optimisation of preventive maintenance cost. This can further boost up the prospects of Indian industry to offer the products at globally competitive prices.

Deshpande, V.S.; Modak, J.P

2003-04-01

108

Ship Roll Damping Control  

DEFF Research Database (Denmark)

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

Blanke, Mogens

2012-01-01

109

Fast-roll inflation  

CERN Document Server

A novel class of exact solutions of inflationary dynamics with a specific form of a scalar potential is given based on a "fast-roll" ansatz, where the even-order slow-roll parameters approach to a nonnegligible constants while the odd ones are asymptotically vanishing in the quasi-de Sitter regime. Due to the rapid evolution of the background dynamics, the would-be decaying mode of the linear curvature perturbation may behave as a growing mode depending on the value of the model parameter, while the other mode remains constant. For the parameters giving a slightly red-tilted primordial power spectrum, the unwanted anomalous growth of the curvature perturbation is inevitable, which is similar to the case of the so-called ultra-slow-roll inflation.

Motohashi, Hayato; Yokoyama, Jun'ichi

2014-01-01

110

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

111

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.

Blanke, Mogens Technical University of Denmark,

2010-01-01

112

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

Scientific Electronic Library Online (English)

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

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

2013-02-01

113

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

Directory of Open Access Journals (Sweden)

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

Ricardo Floriano

2013-02-01

114

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

Directory of Open Access Journals (Sweden)

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

Ricardo Floriano

2012-01-01

115

Slitting criterion for various rolling speeds in MSR rolling process  

Directory of Open Access Journals (Sweden)

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

A. Stefanik

2008-03-01

116

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

117

Welding of stainless steels preceeding rolling  

International Nuclear Information System (INIS)

The E.O. Paton Electrowelding Institute has done experimental work on single-sided consumable heated electrode welding of austenitic, ferritic and martensitic steels with thicknesses up to 6.0 mm for joining roll ends in rolling mill production. The properties of the welds were studied. In laboratory conditions the rollability of the seams was investigated and the effect of thermal treatment on rollability evaluated. The use of welding wire which gives seams of austenitic structure is desirable. Recommended regimes are discussed. It is shown that the possibility exists, in principle, of applying crushed-edge seam contact welding to the joining of stainless steel rolls. (author)

118

Walk and roll robot  

Science.gov (United States)

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

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

2011-01-01

119

Modernitetens Rolle Under Holocaust  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Jespersen, Simon M.

2012-01-01

120

Internal defects in rolls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The report describes an investigation concerning two types of internal defects, axis-centered defects and near-surface defects, in rolls. Thesis for bachelor’s degree in mechanical engineering (22.5p), at the institution for engineering, physics and mathematics, Karlstad University. Ordered by Scana Steel Björneborg AB. Scana Steel Björneborg AB is one of Europe’s leading producers of heavy free-form forgings and has its own steel plant, forge, heating treatment facility and machine par...

Skoglund, Thomas

2008-01-01

 
 
 
 
121

Rolling shutter distortion correction  

Science.gov (United States)

As opposed to the global shutter, which starts and stops the light integration of each pixel at the same time by incorporating a sample-and-hold switch with analog storage in each pixel, the electronic rolling shutter found in most low-end CMOS image sensors today collects the image data row by row, analogous to an open slit that scans over the image sequentially. Each row integrates the light when the slit passes over it. Therefore, the scanlines of the image are not exposed at the same time. This sensor architecture creates an objectionable geometric distortion, known as the rolling shutter effect, for moving objects. In this paper, we address this problem by using digital image processing techniques. A mathematical model of the rolling shutter is developed. The relative image motion between the moving objects and the camera is determined by block-based motion estimation. A Bezier curve fitting is applied to smooth the resulting motion data , which are then used for the alignment of scanlines. The basic ideas behind the algorithm presented here can be generalized to deal with other complicated cases.

Liang, Chia-Kai; Peng, Yu-Chun; Chen, Homer

2005-07-01

122

Tuning Swiss roll metamaterials  

International Nuclear Information System (INIS)

The 'Swiss roll' metamaterial is well suited to operation in the radiofrequency range because it has a low resonant frequency, a strong magnetic response and is electrically very small. However, the elements have to be individually produced, leading to significant variation in the resonant frequency. It is therefore necessary to tune the elements to a target frequency. Three methods for achieving this are described: attaching capacitatively coupled sleeves or discrete capacitors for static tuning, and using a varactor diode to provide electrically controllable tuning. In the last case, the switching time is found to be <1 ms, making dynamic tuning a real possibility.

123

Tuning Swiss roll metamaterials  

Energy Technology Data Exchange (ETDEWEB)

The 'Swiss roll' metamaterial is well suited to operation in the radiofrequency range because it has a low resonant frequency, a strong magnetic response and is electrically very small. However, the elements have to be individually produced, leading to significant variation in the resonant frequency. It is therefore necessary to tune the elements to a target frequency. Three methods for achieving this are described: attaching capacitatively coupled sleeves or discrete capacitors for static tuning, and using a varactor diode to provide electrically controllable tuning. In the last case, the switching time is found to be <1 ms, making dynamic tuning a real possibility.

Wiltshire, M C K, E-mail: michael.wiltshire@imperial.ac.u [Imaging Sciences Department, Clinical Sciences Centre, Imperial College London, Hammersmith Hospital Campus, Ducane Road, London W12 0NN (United Kingdom)

2009-10-21

124

Quantum rolling tachyon  

International Nuclear Information System (INIS)

We consider the quantum treatment of the rolling tachyon background describing the decay of D-branes in the limit of weak string coupling. We focus on the propagation of an open string in the fluctuating background and show how the boundary string action is modified by quantum effects. A bilocal term in the boundary action is generated which, however, does not spoil the vanishing of the ? function at one loop. The propagation of an open string for large times is found to be very strongly suppressed

125

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...

2009-01-01

126

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

127

A new transducer for roll gap measurements of the roll pressure distribution and the friction condition in cold flat rolling  

DEFF Research Database (Denmark)

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

Wanheim, Tarras; Henningsen, Poul

2005-01-01

128

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

129

Mechanical of beryllium deformation and hardening at cold rolling  

International Nuclear Information System (INIS)

Beryllium rolling has been made on DUO-80 mills and quarto 15-35 with reductions of 0.2-1.0% for the run. A mechanism of beryllium deformation at cold rolling is determined by dislocations interaction with additive inclusions. The fracture of inclusion with microcracks formations is possible during deformation. At cold rolling of beryllium it is necessary to control the value of tensile stress in the metal to prevent the propagation of microcracks formed during inclusons cutting

130

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.

131

Quality assessment of rolled strip produced by compact versus conventional rolling  

International Nuclear Information System (INIS)

In continuous casting and rolling, the major factors that influence the quality are frequently interrelated and dependent on each other, with complex confluent relationships. When one of these factors changes, e.g. the temperature, not only is the rolling force affected, but the torque and surface properties, as kinematic boundary conditions, changes as well. The same is valid for the geometric quality parameters, consisting of thickness, profile, flatness, width and wedge, as well as for surface roughness. In order to be able to predict and improve the expected quality of the rolled sheet, detailed analysis of all these factors is necessary. The steel quality-producing of the new compact strip production technique as compared to as an integrated mill is studied by using modern data mining tools, primarily the Self-Organizing Map (SOM) approach. The data are gathered at several steel mills. In this paper data from two mills is analyzed using a bench marking approach. (author)

132

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

133

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)

134

Manufacturing of molybdenum tubes by pressing and skew rolling  

International Nuclear Information System (INIS)

A study was made on the quality of tube billets and molybdenum cast tubes, manufactured by pressing and the following skew rolling. The structure of the device for increasing the stability of exit side of screw rolling vacuum mill is suggested

135

Determination of cold rolling parameters providing required ductility of tubes  

International Nuclear Information System (INIS)

The effect of cold rolling parameters on change in plasticity of tubes of austenitic steels of the Kh18N10T type is shown. Main parameters affecting the decrease of plasticity are reduction in diameter and free reduction. Permissible values of these qualities providing tube fabrication on cold rolling mill witth the required value of relative elongation

136

Nonlinear Observers for Parametric Roll  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Olsen, Gunnhild Konstanse Hoff

2012-01-01

137

Steel balls forming by cross rolling with upsetting  

Directory of Open Access Journals (Sweden)

Full Text Available The paper describes a process of forming four balls with a diameter of 22 mm by means of cross rolling with upsetting. The paper also presents the tool used to form semi-finished balls. Owing to the application of the finite element method (FEM, the course of the rolling process as well as temperature and strain distributions in the obtained balls could be presented. The rolling tests conducted in laboratory conditions at the Lublin University of Technology have proved that the balls produced with the developed rolling method meet the demands for grinding media used in ball mills.

Z. Pater

2013-01-01

138

On Rolling Loaded Dice  

Science.gov (United States)

When an unfair die is tossed, what are the factors that determine the side upon which it lands? Sir Hermann Bondi (see European Journal of Physics 14, pp. 136-140) asked a related theoretical question in 1993 with the intention of determining the theoretical probability of a coin landing on its edge. He notes that the center of mass, the coefficients of restitution and friction, and the radius of gyration all play a role, perhaps. A simple model assumes that the probability of landing on a particular side is proportional to the solid angle subtended from the center of mass, but this model predicts too few base landings for tall cylinders, and too many rolling landings for squatty cylinders. Here we propose a thermodynamic modification of this model which qualitatively improves the match between experiment and theory by introducing an effective ``temperature'' parameter. We apply the model to several different geometrical shapes where the landing odds are not even, including right circular cylinders, rectangular prisms, hemispheres and semi-cylinders. We obtain, perhaps unreasonably, somewhat promising results.

White, Gary

2006-03-01

139

Ultra-thin rolled glass  

Energy Technology Data Exchange (ETDEWEB)

Rolled glass has overtaken float glass in PV. But now the producers of this textured glass are under pressure to drive down costs. The glass manufacturer Glasfabrik Lamberts has opted for 2 mm this glass and customized solutions.

Roepcke, Ina

2012-11-01

140

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.

 
 
 
 
141

The thermal and metallurgical state of steel strip during hot rolling: Part II. Factors influencing rolling loads  

Science.gov (United States)

Traditional models for computing roll forces during hot rolling generally ignore the steep thermal gradients set up in the through-thickness direction due to roll chilling and deformation heat. In this paper, Alexander’s model has been modified to account for the effect of thermal gradients on roll forces. Flow stress data have been obtained by conducting tests on a cam plastometer and a Gleeble 1500 for a 0.05 pct carbon, a 0.34 pct carbon, and a 0.07 pct carbon with 0.024 pct niobium steel for temperatures and strain rates attained in each of the stands on Stelco’s Lake Erie Works (LEW) hot-strip mill. The hyperbolic sine equation has been shown to fit the data and is capable of predicting flow stress over a range of temperatures and strain rates. Simulations of the industrial operation have been conducted on the pilot mill at CANMET, and it has been shown by comparing predicted and measured roll forces that the friction coefficient is reduced from 0.3 to ˜R 0.35 to 0.25 in the presence of a lubricant. It has also been shown that incorporating the steep thermal gradients in the roll-bite zone increases predicted roll forces by 6 to ˜R 10 pct over the values computed based on centerline temperatures. The model has been validated also by comparing predictions with roll forces measured on the industrial mill.

Devadas, C.; Baragar, D.; Ruddle, G.; Samarasekera, I. V.; Hawbolt, E. B.

1991-02-01

142

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

143

AISI/DOE Advanced Process Control Program Vol. 3 of 6: MICROSTRUCTURAL ENGINEERING IN HOT-STRIP MILLS Part 2 of 2: Constitutive Behavior Modeling of Steels Under Hot-Rolling Conditions  

Energy Technology Data Exchange (ETDEWEB)

This report describes the development of models for predicting (1) constitutive behaviors and (2) mechanical properties of hot-rolled steels as functions of chemical composition, microstructural features, and processing variables. The study includes the following eight steels: A36, DQSK, HSLA-V, HSLA-Nb, HSLA-50/Ti-Nb, and two interstitial-free (IF) grades. These developed models have been integrated into the Hot-Strip Mill Model (HSMM), which simulates the hot strip rolling mills and predicts the mechanical properties of hot-rolled products. The HSMM model has been developed by the University of British Columbia-Canada as a part of project on the microstructural engineering in hot-strip mills.

Yi-Wen Cheng; Patrick Purtscher

1999-07-30

144

Roll casting of 5182 aluminium alloy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2009-01-01

145

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

146

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

147

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

148

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

2012-01-01

149

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

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} A composite structure roller rings was fabricated by centrifugal casting. {yields} The roller rings consisted of outer WCP/Fe-C composites layer and inner Fe-C alloy matrix. {yields} 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/cm{sup 2}. {yields} The wear resistance of the roller rings excelled that of high-speed steel, and approached to that of the WC hard alloy roll. {yields} The production cost of the WCP/Fe-C composites roller ring decreased by 50%. - Abstract: Tungsten carbide particle (WC{sub P}) 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 WC{sub P} 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 WC{sub P} 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/cm{sup 2}; 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 WC{sub P}-volume-fraction in working-layer were obtained for both of them, but the production cost of the WC{sub P}/Fe-C composites roller ring decreased by 50%.

Song Yanpei, E-mail: sypei@mail.haust.edu.cn [School of Material Science and Engineering, Henan University of Science and Technology, No 48 Xiyuan Road, Luoyang 471003 (China); Li Xiuqing; Bi Shuangxu [School of Material Science and Engineering, Henan University of Science and Technology, No 48 Xiyuan Road, Luoyang 471003 (China)

2010-09-15

150

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%.

151

Rolling tachyons in string cosmology  

International Nuclear Information System (INIS)

We study the role of rolling tachyons in the cosmological model with dilatonic gravity. In the string frame, flat space solutions of both initial-stage and late-time are obtained in closed form. In the Einstein frame, we show that every expanding solution is decelerating

152

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

153

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

154

Evaluation of roll compaction as a preparation method for hydroxypropyl cellulose-based matrix tablets  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Roll compaction was applied for the preparation of hydroxypropyl cellulose (HPC)-based sustained-release matrix tablets. Matrix tablets made via roll compaction exhibited higher dosage uniformity and faster drug release than direct-compacted tablets. HPC viscosity grade, roll pressure, and milling speed affected tablet properties significantly. Roll compaction seems to be an adequate granulation method for the preparation of HPC-based matrix tablets due to the simplicity of the process, less ...

Jeon, Imjak; Gilli, Tiziana; Betz, Gabriele

2011-01-01

155

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

156

Rolling element fatigue testing of gear materials  

Science.gov (United States)

Rolling element fatigue lives of nine alloys were evaluated in Rolling Contact (RC) rigs. Test conditions included a Hertzian stress at 4,826 MPa (700 ksi), a rolling speed of 6.23 m/sec (245 in/sec.). Tests were run with a Type I oil (MIL-L-7808G) at room temperature. B-10 lives (10% failure rate) of alloys were compared versus reference alloys, VIM-VAR AISI M-50 and VAR AISI 9310. Six case carburizing alloys (AISI 9310, CBS600, CBS1000M, EX00014, Vasco X-2 and EX00053) and three through-hardening alloys (AISI M-50, VascoMax 350 and Vasco Matrix 2 evaluated, showed RCF performance inferior or equivalent to that of AISI 9310 and AISI M-50. It was also found that the effects of vacuum melting processes, different tempering temperatures, freezing cycle during heat treating, shot peening, gold plating and chrome plating employed in the present investigation did not significantly affect RCF life.

Nahm, A. H.

1978-01-01

157

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.)

158

Micromagnetic testing for rolled steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Wolter, B.; Dobmann, G.

2006-01-01

159

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

160

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

 
 
 
 
161

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

DEFF Research Database (Denmark)

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

Wanheim, Tarras; Henningsen, Poul

2006-01-01

162

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

163

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

164

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

165

How rolling forecasting facilitates dynamic, agile planning.  

Science.gov (United States)

Rolling forecasting may be used to replace or supplement the annual budget process. The rolling forecast typically builds on the organization's strategic financial plan, focusing on the first three years of plan projections and comparing the strategic financial plan assumptions with the organization's expected trajectory. Leaders can then identify and respond to gaps between the rolling forecast and the strategic financial plan on an ongoing basis. PMID:24340653

Miller, Debra; Allen, Michael; Schnittger, Stephanie; Hackman, Theresa

2013-11-01

166

Rolling textures of niobium and molybdenum  

International Nuclear Information System (INIS)

Niobium and molybdenum were rolled at ambient temperature. The crystallographic orientation distribution of the 50%, 60% and 70% deformed samples was investigated by means of quantitative texture analysis. Simulations of the rolling textures were performed using the Relaxed Constraints Taylor Theory. It was shown that dislocation movement took place on {110} and {112} glide planes. After 70% rolling deformation additional glide on {123} planes occurred in case of niobium. (orig.)

167

Fluid management in roll-to-roll nanoimprint lithography  

Science.gov (United States)

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

Jain, A.; Bonnecaze, R. T.

2013-06-01

168

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

Science.gov (United States)

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

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

2013-12-01

169

8.G Shipping Rolled Oats  

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: Rolled oats (dry oatmeal) come in cylindrical containers with a diameter of 5 inches and a height of 9$\\frac12$ inches. These containers are shipped to...

170

CRITICAL WAVE EPISODES FOR ASSESSMENT OF ROLL  

DEFF Research Database (Denmark)

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

Jensen, JØrgen Juncher; Pedersen, Preben Terndrup

2006-01-01

171

A Framework for Rolling Stock Rescheduling  

DEFF Research Database (Denmark)

Rolling Stock schedules are typically made months or weeks prior to the date of execution. It is, however, rare that everything goes exactly as planned due to internal and external factors on the day of operation. If the magnitude of the disturbances is small then the problems may be absorbed by network buffer times. However, if the problems are more severe, changes must be made to the rolling stock schedule. In this talk we will discuss the Rolling Stock Rescheduling problem and Disruption Management. We will present our current work and planned future work on a framework for solving the Rolling Stock in a disruption context.

Haahr, JØrgen Thorlund; Lusby, Richard Martin

172

Whirlwind Rolling Process of Slender Shaft  

Directory of Open Access Journals (Sweden)

Full Text Available In order to solve the problem of slender shaft which is easy bended and deformed for its big slenderness ration and poor rigidity, the method of whirlwind rolling with Tri-tools is designed. This paper introduces the principle and the process of stress analysis. With the help of ABAQUS finite element simulation software, the 3D model of whirling rolling is established. The rolling process is simulated by the software and summarizes the influence of quality factors during the whirlwind rolling process.

Zhang Hong

2013-05-01

173

Interactions Between Stably Rolling Leukocytes In Vivo  

CERN Document Server

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

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

2003-01-01

174

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

175

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.

176

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

177

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2006-01-01

178

Roll forming of eco-friendly stud  

Science.gov (United States)

In order to manufacture an eco-friendly stud, the sheared pattern is designed by the Taguchi method and expanded by the side rolls. The seven geometrical shape of sheared pattern are considered in the structural and thermal analyses to select the best functional one in terms of the durability and fire resistance of dry wall. For optimizing the size of the sheared pattern chosen, the L9 orthogonal array and smaller-the-better characteristics of the Taguchi method are used. As the roll gap causes forming defects when the upper-and-lower roll type is adopted for expanding the sheared pattern, the side roll type is introduced. The stress and strain distributions obtained by the FEM simulation of roll-forming processes are utilized for the design of expanding process. The expanding process by side rolls shortens the length of expanding process and minimizes the cost of dies. Furthermore, the stud manufactured by expanding the sheared pattern of the web is an eco-friend because of the scrapless roll-forming process. In addition, compared to the conventionally roll-formed stud, the material cost is lessened about 13.6% and the weight is lightened about 15.5%.

Keum, Y. T.; Lee, S. Y.; Lee, T. H.; Sim, J. K.

2013-12-01

179

49 CFR 661.11 - Rolling stock procurements.  

Science.gov (United States)

... Rolling stock procurements. 661.11... Rolling stock procurements. (a) The...not apply to the procurement of buses and other rolling stock (including train control...manufacturing process to produce...

2010-10-01

180

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

Science.gov (United States)

...2010-04-01 2010-04-01 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...

2010-04-01

 
 
 
 
181

Multi-field coupled numerical simulation of hot reversible rolling process of GCr15 steel rod  

Science.gov (United States)

In this paper, based on rolling technology of hot reversible rolling mill, a multi-filed coupled finite element (FE) model of hot reversible rolling process of large dimension cross-section GCr15 steel rod is established. Thermal, mechanical and microstructural phenomena during the rolling process are coupled in the model. By employing grain growth experiment, double and single hit hot compression experiments, the austenite grain size growth mathematical model and recrystallization behavior mathematical models are determined. And a designed subprogram is coupled in the FE model. Actual hot reversible rolling process of GCr15 steel is simulated using the model and the distribution and evolution of different filed-variables, such as temperature, effective strain and austenite grain size are obtained. To verify the model predictions, hot rolling experiments are carried out and the temperature and microstructure of the rolling metal are compared with the predicted results. The comparison between the two sets of data shows a good agreement.

Gu, Sendong; Zhang, Liwen; Ruan, Jinhua; Mei, Hongyu; Zhen, Yu; Shi, Xinhua

2013-05-01

182

OPTIMISE - Deliverable D4.1, Deliver preliminary samples made by two axis rolling to UNIVERSITY OF TWENTE, month 6  

DEFF Research Database (Denmark)

This report describes the preliminary samples that were delivered to University of Twente (UT). It was decided not to deliver samples made by two axis rolling but instead deliverer samples which were reduce by square drawing and flat rolled in a standard rolling mill. The reason for that will be explained before the results from the actual deliverables will be described.

Eriksen, Morten

2002-01-01

183

Roll Casting of Aluminum Alloy Clad Strip  

Science.gov (United States)

Casting of aluminum alloy three layers of clad strip was tried using the two sets of twin roll casters, and effects of the casting parameters on the cladding conditions were investigated. One twin roll caster was mounted on the other twin roll caster. Base strip was 8079 aluminum alloy and overlay strips were 6022 aluminum alloy. Effects of roll-load of upper and lower casters and melt temperature of the lower caster were investigated. When the roll-load of the upper and lower caster was large enough, the overlay strip could be solidified and be connected. The overlay strip could be connected when the melt of the overlay strip cast by the lower caster was low enough. Sound three layers of clad strip could be cast by proper conditions.

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

2011-01-01

184

Effect of ultrasonic oscillations on steel rolling  

International Nuclear Information System (INIS)

The effect of radial ultrasonic oscillations on rolling has been studied. Plates and pipes made of the St3 and 08Kh18N10T steel were rolled at 20 and at 1200 deg C. Ultrasonic waves proved to reduce pressure on the rollers by 9-14%, this eventually leading to higher efficiency of rolling. Hot rolling involving ultrasonic treatment decreased the ultrimate strength and yield point of both steels by 5-10% and increased relative elongation on account of uniform contraction. Cold ultrasound-involving rolling decreased the ultimate strength and the yield point of the St3 steel, hardly affecting those of the 08Kh18N10T steel

185

Roll Casting of Aluminum Alloy Clad Strip  

International Nuclear Information System (INIS)

Casting of aluminum alloy three layers of clad strip was tried using the two sets of twin roll casters, and effects of the casting parameters on the cladding conditions were investigated. One twin roll caster was mounted on the other twin roll caster. Base strip was 8079 aluminum alloy and overlay strips were 6022 aluminum alloy. Effects of roll-load of upper and lower casters and melt temperature of the lower caster were investigated. When the roll-load of the upper and lower caster was large enough, the overlay strip could be solidified and be connected. The overlay strip could be connected when the melt of the overlay strip cast by the lower caster was low enough. Sound three layers of clad strip could be cast by proper conditions.

186

Automated Procedure for Roll Pass Design  

Science.gov (United States)

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

Lambiase, F.; Langella, A.

2009-04-01

187

Computational Analysis of Ares I Roll Control System Jet Interaction Effects on Rolling Moment  

Science.gov (United States)

The computational flow solver USM3D was used to investigate the jet interaction effects from the roll control system on the rolling moment of the Ares I full protuberance configuration at wind tunnel Reynolds numbers. Solutions were computed at freestream Mach numbers from M = 0.5 to M = 5 at the angle of attack 0deg, at the angle of attack 3.5deg for a roll angle of 120deg, and at the angle of attack 7deg for roll angles of 120deg and 210deg. Results indicate that the RoCS housing provided a beneficial jet interaction effect on vehicle rolling moment for M > or = 0.9. Most of the components downstream of the roll control system housing contributed to jet interaction penalties on vehicle rolling moment.

Deere, Karen A.; Pao, S. Paul; Abdol-Hamid, Khaled S.

2011-01-01

188

Investigation into power parameters during rapid rolling of high-alloyed and difficult-deformed alloys with technological lubricants  

International Nuclear Information System (INIS)

The effect of the rolling speed (from 4.5 to 15.7 m/s) and rolling lubricants on the force prameters involved in the rolling of high-alloy and high-resistance alloys has been studied under laboratory conditions on a 300 high-speed mill. The experimental rolling of high-alloy and high-resistance alloys has shown the possibility of rolling such alloys at high speed without adverse affecting their physicomechanical properties, with a view to increasing the mill production and for a fuller utilization of their narrow rolling temperature range. Therewith, the use of rolling lubricants reduces the metal pressure on the rolls by 15 to 20%

189

Rolling Contact Force Energy Reconstruction  

Science.gov (United States)

Knowledge of the forces at the wheel-rail contact is fundamental to estimate the consequences in terms of noise and vibration. The traditional use of strain gauges mounted on the wheel web and axle is not capable of determining the high-frequency content of the contact force. Measurements made on the rail are characterized by the spatial variability of input-output transfer functions which makes it difficult to estimate the contact force by simple inversion of the point frequency response function. In this study the problem of rolling contact force reconstruction has been approached through the following steps: (i) the track has been characterized precisely for a finite length by the analysis of the time series of several impacts supplied with an instrumented hammer by using an ARMAX model that proved to be capable of modelling the vertical dynamics of the rail up to 5 kHz; (ii) the response of the rail has been simulated with a random force acting on the system, and the variability of the transfer function has been taken into account by distributing the force on adjacent elements; (iii) the simulated response has been compared with the rail acceleration measured for the passage of several trains; (iv) the wheel-rail contact force has been estimated with a closed-loop algorithm. It has thus been possible to reconstruct the13octave power spectrum of contact forces with a simple and stable iterative procedure. Forces reconstructed from different sensors were found to be practically the same for a given wheel; forces from nominally similar wheels are statistically examined and partial results of comparisons made on different rolling stock are shown.

BRACCIALI, A.; CASCINI, G.

2000-09-01

190

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

Directory of Open Access Journals (Sweden)

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

H. Watari

2006-02-01

191

'Slings' enable neutrophil rolling at high shear.  

Science.gov (United States)

Most leukocytes can roll along the walls of venules at low shear stress (1?dyn?cm?2), but neutrophils have the ability to roll at tenfold higher shear stress in microvessels in vivo. The mechanisms involved in this shear-resistant rolling are known to involve cell flattening and pulling of long membrane tethers at the rear. Here we show that these long tethers do not retract as postulated, but instead persist and appear as 'slings' at the front of rolling cells. We demonstrate slings in a model of acute inflammation in vivo and on P-selectin in vitro, where P-selectin-glycoprotein-ligand-1 (PSGL-1) is found in discrete sticky patches whereas LFA-1 is expressed over the entire length on slings. As neutrophils roll forward, slings wrap around the rolling cells and undergo a step-wise peeling from the P-selectin substrate enabled by the failure of PSGL-1 patches under hydrodynamic forces. The 'step-wise peeling of slings' is distinct from the 'pulling of tethers' reported previously. Each sling effectively lays out a cell-autonomous adhesive substrate in front of neutrophils rolling at high shear stress during inflammation. PMID:22763437

Sundd, Prithu; Gutierrez, Edgar; Koltsova, Ekaterina K; Kuwano, Yoshihiro; Fukuda, Satoru; Pospieszalska, Maria K; Groisman, Alex; Ley, Klaus

2012-08-16

192

Slings enable neutrophil rolling at high shear  

Science.gov (United States)

Most leukocytes can roll along the walls of venules at low shear stress (1 dyn/cm2), but neutrophils have the ability to roll at 10-fold higher shear stress in microvessels in vivo1,2. The mechanisms involved in this shear-resistant rolling are known to involve cell flattening3 and pulling of long membrane tethers at the rear4–6. Here, we show that these long tethers do not retract as postulated6,7, but instead persist and appear as ‘slings’ at the front of rolling cells. We demonstrate slings in a model of acute inflammation in vivo and on P-selectin in vitro, where P-selectin-glycoprotein-ligand-1 (PSGL-1) is presented as discrete sticky patches while LFA-1 is expressed over the entire length on slings. As neutrophils roll forward, slings wrap around the rolling cells and undergo a step-wise peeling from the P-selectin substrate enabled by the failure of PSGL-1 patches under hydrodynamic forces. The ‘step-wise peeling of slings’ is distinct from the ‘pulling of tethers’ reported previously4–6,8. Each sling effectively lays out a cell-autonomous adhesive substrate in front of neutrophils rolling at high shear stress during inflammation. PMID:22763437

Sundd, Prithu; Gutierrez, Edgar; Koltsova, Ekaterina K.; Kuwano, Yoshihiro; Fukuda, Satoru; Pospieszalska, Maria K.; Groisman, Alexander; Ley, Klaus

2012-01-01

193

Minimizing the edge buckling of the cold roll-forming process  

Science.gov (United States)

In this work, the cold roll-forming process was numerically simulated by MSC SuperForm 2002 software based on finite element method. The strips were modelled with U-profile and a pre-punched hole located at the web zone was introduced. Two different configurations of the roll-forming mills were simulated, named as the Conventional and Curved. The conventional roll-forming mill was obtained by using the same diameters of the bottom rolls. The downhill roll-forming mill was achieved by increasing the diameters of the bottom rolls. This study investigated the occurrence of edge buckling in the hole lateral edge of the pre-punched sheet during the forming process. It could be concluded that, during the cold roll-forming process, reducing or even eliminating the compression stress in the web zone by the downhill roll-forming mill is possible to minimize occurrence of the edge buckling in the hole lateral edge of the pre-punched sheet during the forming process.

Cavaguti, M.; Ferreira, J. V.

2010-06-01

194

Minimizing the edge buckling of the cold roll-forming process  

International Nuclear Information System (INIS)

In this work, the cold roll-forming process was numerically simulated by MSC SuperForm 2002 software based on finite element method. The strips were modelled with U-profile and a pre-punched hole located at the web zone was introduced. Two different configurations of the roll-forming mills were simulated, named as the Conventional and Curved. The conventional roll-forming mill was obtained by using the same diameters of the bottom rolls. The downhill roll-forming mill was achieved by increasing the diameters of the bottom rolls. This study investigated the occurrence of edge buckling in the hole lateral edge of the pre-punched sheet during the forming process. It could be concluded that, during the cold roll-forming process, reducing or even eliminating the compression stress in the web zone by the downhill roll-forming mill is possible to minimize occurrence of the edge buckling in the hole lateral edge of the pre-punched sheet during the forming process.

195

Flow Stress Evaluation in Hot Rolling of Steel  

Science.gov (United States)

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

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

2014-08-01

196

Off-line calculation of pass schedule for hot rolling stainless steel strip and establishment of model parameters for on-line set up calculation  

International Nuclear Information System (INIS)

In this paper, the method to calculate the roughing and finishing rolling forces is described. The way to establish the model parameters for on-line process set up calculation during developing hot rolling stainless steel strip in 2050mm hot rolling mill of Baosteel, is also introduced. Rolling test shows that the rolling forces calculated by on-line process set up model agree well with measured data. (author)

197

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

198

Hot rolling of intermetallics FeAl phase based alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The one of major problem restricting universal employment of intermetallic phase base alloy istheir low plasticity which leads to hampering their development as construction materials. The following workconcentrates on possibilities to form through rolling process the alloys with various aluminium content.Design/methodology/approach: After casting and annealing, alloy specimens were subjected to axialsymmetriccompression at temperatures ranging from 900 to 1200°C at 10 s-1 strain rates. In order to analyse theprocesses which take place during deformation, the specimens after deformation were intensely cooled with water.Structural examination was carried out using light microscopy. The process was conducted on the K -350 quartorolling mill used for hot rolling of flat products. The process was conducted in some stages in at temperaturesranging from 1200-900°C:Findings: The research carried out enabled the understanding of the phenomena taking place during hot rolling ofthe investigated alloy. An alloy with 38%at. aluminium concentration can be plastically formed at a temperature of upto 900°C, which has been also confirmed in plastometric studies conducted in the form of hot compression tests.Research limitations/implications:Practical implications: The obtained sheets can be used as constructional elements working in complex stressfields, at a high temperature and corrosive environmentsOriginality/value: The tests have shown that it is possible to form the investigated alloys through rolling processingonly where shields are applied. Rolling of the alloys without shields led to the occurrence of a grid of cracks.

G. Niewielski

2008-02-01

199

Designing Rolling-Element Bearings  

Science.gov (United States)

Bearing Analysis Tool (BAT) is a computer program for designing rolling-element bearings for cryogenic turbomachines. BAT provides a graphical user interface (GUI) that guides the entry of data to develop mathematical models of bearings. The GUI breaks model data into logical subsets that are entered through logic-driven input screens. The software generates a threedimensional graphical model of a bearing as the data are entered. Most dataentry errors become immediately obvious in the graphical model. BAT provides for storage of all the data on a shaft/bearing system, enabling the creation of a library of proven designs. Data from the library can be transferred to subsequent projects by use of simple cut-and-paste routines. BAT includes a library of temperature- dependent cryogenic bearing-material properties for use in the mathematical models. BAT implements algorithms that (1) enable the user to select combinations of design and/or operating-condition parameters, and then (2) automatically optimize the design by performing trade studies over all of the parameter combinations. This feature enables optimization over a large trade space in a fraction of the time taken when using prior bearingmodel software.

Moore, James D., Jr.

2007-01-01

200

Roll measurement of Tevatron dipoles and quadrupoles  

Energy Technology Data Exchange (ETDEWEB)

In 2003 a simple digital level system was developed to allow for rapid roll measurements of all dipoles and quadrupoles in the Tevatron. The system uses a Mitutoyo digital level and a PC running MS WINDOWS XP and LAB VIEW to acquire data on the upstream and downstream roll of each magnet. The system is sufficiently simple that all 1,000 magnets in the Tevatron can be measured in less than 3 days. The data can be quickly processed allowing for correction of rolled magnets by the Fermilab alignment group. Data will be presented showing the state of the Tevatron in 2003 and the changes in rolls as measured in each shutdown since then.

Volk, J.T.; Elementi, L.; Gollwitzer, K.; Jostlein, H.; Nobrega, F.; Shiltsev, V.; Stefanski, R.

2006-09-01

 
 
 
 
201

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

202

33 CFR 159.107 - Rolling test.  

Science.gov (United States)

...POLLUTION MARINE SANITATION DEVICES Design, Construction...Rolling test. (a) The device, with liquid retention components, if any, filled with water to half of their volume...the centerline of the device, no more than 6...

2010-07-01

203

14 CFR 25.349 - Rolling conditions.  

Science.gov (United States)

...manner, considering the principal masses furnishing the reacting inertia forces. (a) Maneuvering. The following conditions...rolling velocity may be assumed in the absence of a rational time history investigation of the maneuver. (2) At V A,...

2010-01-01

204

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)

205

Disk partition function and oscillatory rolling tachyons  

Energy Technology Data Exchange (ETDEWEB)

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

Jokela, Niko [Helsinki Institute of Physics, University of Helsinki, PO Box 64, FIN-00014 (Finland); Jaervinen, Matti [Helsinki Institute of Physics, University of Helsinki, PO Box 64, FIN-00014 (Finland); Keski-Vakkuri, Esko [Helsinki Institute of Physics, University of Helsinki, PO Box 64, FIN-00014 (Finland); Majumder, Jaydeep [Helsinki Institute of Physics, University of Helsinki, PO Box 64, FIN-00014 (Finland)

2008-01-11

206

Disk partition function and oscillatory rolling tachyons  

International Nuclear Information System (INIS)

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

207

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

208

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

209

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

210

Roll bonding of 6061 aluminum alloy plates  

International Nuclear Information System (INIS)

The roll bonding process is an important application of the solid state welding . in principle, two or more slabs of the materials to be bonded are placed in contact and welded around the edges. then, this assembled set is heated and rolled until the required thickness is obtained. this process is applied to clad the nuclear fuel, with high strength aluminum alloys during fabrication of plate type nuclear fuel elements for research reactors, or to produce many new constructions which have special uses in industrial applications. in the present work, the steps of the hot roll bonding of 6061 aluminum alloy plates were studies by using both microscopic examination and mechanical test namely singe lap shear strength test. also the effect of reduction degree in thickness, the sequence of hot rolling , surface roughness, degassing opening length and holding time on roll bonding process were studied. the results obtained due to variations in the above parameters are discussed with respect to their effects on the roll bonding of 6061 aluminum alloy plates as well as their effects on the specifications of the fuel plates

211

Partition Decomposition for Roll Call Data  

CERN Document Server

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

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

2011-01-01

212

Strip edge cracking simulation in cold rolling  

Science.gov (United States)

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

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

2011-01-01

213

Strip edge cracking simulation in cold rolling  

International Nuclear Information System (INIS)

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

214

Recent developments in modeling of hot rolling processes: Part I - Fundamentals  

Science.gov (United States)

The numerical simulation of industrial rolling processes has gained substantial relevance over the past decades. A large variety of models have been put forward to simulate single and multiple rolling passes taking various interactions between the process, the microstructure evolution and the rolling mill into account. On the one hand, these include sophisticated approaches which couple models on all scales from the product's microstructure level up to the elastic behavior of the roll stand. On the other hand, simplified but fast models are used for on-line process control and automatic pass schedule optimization. This publication gives a short overview of the fundamental equations used in modeling of hot rolling of metals. Part II of this paper will present selected applications of hot rolling simulations.

Hirt, Gerhard; Bambach, Markus; Seuren, Simon; Henke, Thomas; Lohmar, Johannes

2013-05-01

215

Wear phenomena of spinning rolls for stone wool production  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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. Pred...

Klimpel, A.; Dobrzan?ski, L. A.; Lisiecki, A.; Janicki, D.

2006-01-01

216

Numerical simulation of wear of basalt lava spinning rolls  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Lisiecki, A.; Klimpel, A.; Janicki, D.

2006-01-01

217

Hybrid Hot Strip Rolling Force Prediction using a Bayesian Trained Artificial Neural Network and Analytical Models  

Directory of Open Access Journals (Sweden)

Full Text Available The authors discuss the combination of an Artificial Neural Network (ANN with analytical models to improve the performance of the prediction model of finishing rolling force in hot strip rolling mill process. The suggested model was implemented using Bayesian Evidence based training algorithm. It was found that the Bayesian Evidence based approach provided a superior and smoother fit to the real rolling mill data. Completely independent set of real rolling data were used to evaluate the capacity of the fitted ANN model to predict the unseen regions of data. As a result, test rolls obtained by the suggested hybrid model have shown high prediction quality comparatively to the usual empirical prediction models.

Abdelkrim Moussaoui

2006-01-01

218

An Influence Function Method Analysis of Cold Strip Rolling  

Science.gov (United States)

An influence function method has been developed to simulate the asymmetric cold rolling of thin strip with work roll kiss at edges. The numerical simulation model was obtained based on the deformation compatibility of the roll system in rolling and lateral directions. The strip plastic deformation has been considered in the formulation, which is significantly different from the traditional theory of metal rolling. The rolling mechanics and crown of the strip with work roll edge kiss, which are new findings for cold rolling of thin strip, are obtained. A comparison of the rolling force, roll edge kiss force and the strip crown after rolling has been conducted for various cross shear regions in the roll bite. Results show that the calculated strip crown is in good agreement with Ameasured value, and the rolling force and strip crown decrease with an increase of cross shear regions, as well as the work roll edge kiss force and edge wear decrease. The friction also has an influence on the profile of the rolled thin strip.

Jiang, Z. Y.; Wei, D. W.; Tieu, A. K.

219

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

DEFF Research Database (Denmark)

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

Vig, Asger Laurberg; Mäkelä, Tapio

2011-01-01

220

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

Science.gov (United States)

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

Laurberg Vig, Asger; Mäkelä, Tapio; Majander, Päivi; Lambertini, Vito; Ahopelto, Jouni; Kristensen, Andrs

2011-03-01

 
 
 
 
221

Microstructure and properties of hot roll bonding layer of dissimilar metals. 2. Bonding interface microstructure of Zr/stainless steel by hot roll bonding and its controlling  

International Nuclear Information System (INIS)

The hot roll bonding of zirconium and stainless steel inserted with tantalium was investigated using the newly developed rolling mill. The effect of hot rolling temperatures of zirconium/stainless steel joints on bonding interface structure was evaluated. Intermetallic compound layer containing cracks was observed at the bonding interface between stainless steel and tantalium when the rolling temperature was above 1373K. The hardness of the bonding layer of zirconium and tantalium bonded above 1273K was higher than tantalium or zirconium base metal in spite of absence of intermetallic compound. The growth of reaction layer at the stainless steel and tantalium interface and at the tantalium and zirconium interface was conforming a parabolic low when that was isothermally heated after hot roll bonding, and the growth rate was almost same as that of static diffusion bonding without using hot roll bonding process. It is estimated that the strain caused by hot roll bonding gives no effect on the growth of reaction layer. It was confirmed that the dissimilar joint of zirconium and stainless steel with insert of tantalium having the sound bonding interface were obtained at the suitable bonding temperature of 1173K by the usage of the newly developed hot roll bonding process. (author)

222

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

223

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

224

Surface finishing and levelling of thermomechanically hardened rolled steel  

International Nuclear Information System (INIS)

The finishing of high-strength merchant shapes from alloy steel was tried out under industrial conditions with the equipment of metallurgical plants. After thermomechanical hardening in the production line of the rolling mill, 30KhGSN2A and 40Kh1NVA steel rounds 32 and 31 mm in diameter were straightened on a two-roller straightening machine designed by the All-Union Scientific Research Institute for Metallurgical Machinery (VNII Metmash). This made possible subsequent turning and grinding of the rods. The conditions of straightening, turning and grinding have been worked so as to obtain thermomechanically strengthened and ground rolled products approximating the gauged and ground metal in shape geometry and surface finish. It is shown that the labour-consuming operation of turning can be eliminated by reducing the machining pass of the rolled product, and this lowers the labour required for the finishing operations by 75%. After grinding with 40- and 25-grain abrasive wheels, high strength rolled shapes were obtained with a diameter of 30-0.20 mm and a surface finish of class 6-5 satisfying the technical specifications. (author)

225

Microstructure Evolution During Spray Rolling and Heat Treatment of 2124 Al  

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-09-01

226

Development of a twin roll caster for light metals  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Haga, T.

2010-01-01

227

Detection of Parametric Roll on Ships  

DEFF Research Database (Denmark)

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

Galeazzi, Roberto; Blanke, Mogens

2012-01-01

228

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

229

Study of rolled uranium annealing process  

International Nuclear Information System (INIS)

The dilatometric study of rolled uranium clearly shows not only the expansions or contractions induced by stress relief or diffusion of vacancies, but also the slope variations of the cooling curves, which are the best evidence of a texture change. Under the microscope, hard-rolled sheets appear as a mixture of two distinct structures; it is also possible by intermediate annealing to prepare homogeneous sheets of either structure, i.e. twinned or untwinned. All these sheets which have similar textures, undergo at first a primary recrystallization beginning at 320 deg C, then a texture change without any apparent crystal growth, at about 430 deg C. (author)

230

The riddles of rock and roll  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rock and roll has often been equated with rebellion. The genre, though, is just a form of popular music and many of the important players in the game of promoting it were, like the saying goes, only in it for the money. As a rule, music like that will be supportive of the social order rather than inciting resistance against it. So, how did rock and roll acquire its rebellious image? Investigating this question from a sociological perspective, Leo D'Anjou here retells the story of the early be...

Anjou, L. J. M. D.

2003-01-01

231

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

Directory of Open Access Journals (Sweden)

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

Péricles Guedes Alves

2012-12-01

232

Recrystallization behavior of cold-rolled Zr 702  

International Nuclear Information System (INIS)

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

233

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

234

Rolled glass made in Wunsiedel; Walzglas aus Wunsiedel  

Energy Technology Data Exchange (ETDEWEB)

Rolled glass is more popular in the solar industry than float glass. But cost pressure is facing producers of structured glass, too. Lamberts is a glass manufacturers that focuses on 2 mm rolled glass and tailored solutions.

Roepcke, Ina

2012-10-02

235

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

International Nuclear Information System (INIS)

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

236

Tool For Robotic Resistive Roll Welding  

Science.gov (United States)

Roll-welding attachment for robot simple, inexpensive device incorporating modified commercial resistance-welding gun. Modified welding gun easily attaches to end effector of robot. Robot applies welding force and moves electrode wheel along prescribed path. Resistance-welding current starts and stops automatically according to force exerted against workpiece. Used to apply brazing foil to workpiece.

Gilber, Jeffrey L.

1991-01-01

237

Tunable swelling and rolling of microgel membranes.  

Science.gov (United States)

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

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

2014-07-01

238

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

239

Grey Prediction on Rolling Bearing Friction Torque  

Directory of Open Access Journals (Sweden)

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

Xintao Xia

2012-07-01

240

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

 
 
 
 
241

Cosmological constraints on rapid roll inflation  

International Nuclear Information System (INIS)

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

242

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

243

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

244

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

245

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

246

Development and Fabrication of Pineapple Rolled Tart Machine  

Directory of Open Access Journals (Sweden)

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

Azman Hamzah

2011-01-01

247

Theory of rolling: Solution of the Coulomb problem  

Science.gov (United States)

A theory of rolling of round bodies in the normal mode with adhesion conditions satisfied on the entire contact area is proposed. This theory refines the classical Coulomb's theory of rolling in which the rolling moment is directly proportional to the pressing force (e.g., the weight of the rolling body). The rolling moment of cylinders is found to be directly proportional to the pressing force raised to a power of 3/2, and the rolling moment of balls and tori is proportional to the pressing force raised to a power of 4/3. It is shown that the normal mode of uniform rolling can only be provided for a certain ratio of the elastic constants of the materials of the round body and the base forming an ideal pair. The Coulomb problem is solved for the cases of rolling of an elastic cylinder over an elastic half-space, of an elastic ball over an elastic half-space, of an elastic torus over an elastic half-space, and of a cylinder and ball over a tightly stretched membrane. The rolling law is derived for such cases. The rolling friction coefficients, the rolling moment, and the rolling friction force are calculated.

Cherepanov, G. P.

2014-01-01

248

25 CFR 75.6 - Additions to the roll.  

Science.gov (United States)

... § 75.6 Additions to the roll. There shall be added to the roll of the Band the names of persons...persons whose names appear on the roll prepared and approved pursuant...the person adjudged to be the father is either an enrolled...

2010-04-01

249

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

250

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

251

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

Science.gov (United States)

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

Cooper, Khershed P.; Wachter, Ralph F.

2012-10-01

252

Laser direct write system for fabricating seamless roll-to-roll lithography tools  

Science.gov (United States)

Implementations of roll to roll contact lithography require new approaches towards manufacturing tooling, including stamps for roll to roll nanoimprint lithography (NIL) and soft lithography. Suitable roll based tools must have seamless micro- or nano-scale patterns and must be scalable to roll widths of one meter. The authors have developed a new centrifugal stamp casting process that can produce uniform cylindrical polymer stamps in a scalable manner. The pattern on the resulting polymer tool is replicated against a corresponding master pattern on the inner diameter of a centrifuge drum. This master pattern is created in photoresist using a UV laser direct write system. This paper discusses the design and implementation of a laser direct write system targeting the internal diameter of a rotating drum. The design uses flying optics to focus a laser beam along the axis of the centrifuge drum and to redirect the beam towards the drum surface. Experimental patterning results show uniform coatings of negative photoresist in the centrifuge drum that are effectively patterned with a 405 nm laser diode. Seamless patterns are shown to be replicated in a 50 mm diameter, 60 mm long cylindrical stamp made from polydimethylsiloxane (PDMS). Direct write results show gratings with line widths of 10 microns in negative photoresist. Using an FPGA, the laser can be accurately timed against the centrifuge encoder to create complex patterns.

Petrzelka, Joseph E.; Hardt, David E.

2013-03-01

253

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

254

Structure and properties of rolled strips of microalloyed steel type 10KhSND  

International Nuclear Information System (INIS)

The paper presents an investigation of the structure and properties of 16 and 22 mm thick sheets of microalloyed steel of 10KhSND type (10Kh5SND type with a decreased content of nickel) which were rolled on a plate mill and were subjected to normalization or martempering. It is shown that the rolled stock of S390K steel, which was microalloyed with titanium, aluminium and nitrogen, after normalization features high mechanical properties and cold resistance in line with the requirements of state standard GOST 27772. Vanadium microalloying of S390K steel improves the weldability of the rolled products. 4 figs., 3 tabs

255

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)

256

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

257

Plastic-deformation zone length and the allowable speed for ingotless rolling  

Science.gov (United States)

To realize a casting-rolling process in two-high units (mills), it is reasonable to maintain a process speed at which the level of the liquid phase does not fall below the level of the plane passing through the roll axes. Dependences are obtained to estimate possible oscillations in the plastic-deformation zone length with allowance for possible deviations of the ingot-rim thickness and to determine the allowable exit strip velocity that provides the required strain.

Brovman, M. Ya.; Nikolaev, V. A.; Polukhin, V. P.

2007-02-01

258

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

259

Metal flowing of involute spline cold roll-beating forming  

Science.gov (United States)

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

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

2013-09-01

260

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

Science.gov (United States)

...hot-rolled steel from Brazil and Japan, and the suspended investigation...hot-rolled steel from Brazil and Japan, and the suspended investigation...the Commission's Rules of Practice and Procedure, part 201...of hot- rolled steel from Japan (64 FR 34778). Effective...202-205-3088. Limited disclosure of business proprietary information...

2010-04-01

 
 
 
 
261

75 FR 47263 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From the Russian Federation; Final...  

Science.gov (United States)

...Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2010-08-05

262

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

Science.gov (United States)

...Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2011-06-17

263

76 FR 22868 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil: Final Results of...  

Science.gov (United States)

... Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2011-04-25

264

75 FR 19369 - Certain Hot-Rolled Flat-Rolled Carbon Quality Steel Products from Brazil: Preliminary Results of...  

Science.gov (United States)

... Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2010-04-14

265

77 FR 32513 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From the Russian Federation; Preliminary...  

Science.gov (United States)

...Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2012-06-01

266

75 FR 64254 - Certain Hot-Rolled Flat-Rolled Carbon Quality Steel Products From Brazil; Final Results of...  

Science.gov (United States)

...Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2010-10-19

267

75 FR 64700 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil: Preliminary Results of...  

Science.gov (United States)

... Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2010-10-20

268

75 FR 43931 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products from Brazil: Preliminary Results of...  

Science.gov (United States)

... Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2010-07-27

269

75 FR 65453 - Certain Hot-Rolled Flat-Rolled Carbon Quality Steel Flat Products From Brazil: Notice of...  

Science.gov (United States)

...minimum. Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2010-10-25

270

Roll caster for the three-layer clad-strip  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

271

High speed twin roll casting of 6016 aluminium alloy strip  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 allo...

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

2007-01-01

272

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

273

Investigations upon the indefinite rolls quality assurance in multiple regression analysis  

International Nuclear Information System (INIS)

The rolling rolls quality has been enhanced mainly due to the improvements of the chemical compositions of rolls materials. The realization of an optimal chemical composition can constitute a technical efficient mode to assure the exploitation properties, the material from which the rolling mills rolls are manufactured having a higher importance in this sense. This paper continues to present the scientifically results of our experimental research in the area of the rolling rolls. The basic research contains concrete elements of immediate practical utilities in the metallurgical enterprises, for the quality improvements of rolls, having in last as the aim the durability growth and the safety in exploitation. This paper presents an analysis of the chemical composition, the influences upon the mechanical properties of the indefinite cast iron rolls. We present some mathematical correlations and graphical interpretations between the hardness (on the working surface and on necks) and the chemical composition. Using the double and triple correlations which is really helpful in the foundry practice, as it allows us to determine variation boundaries for the chemical composition, in view the obtaining the optimal values of the hardness. We suggest a mathematical interpretation of the influence of the chemical composition over the hardness of these indefinite rolling rolls. In this sense we use the multiple regression analysis which can be an important statistical tool for the 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.

274

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

275

Energy dissipation in a rolling aircraft tire  

Science.gov (United States)

The project is extending an existing finite element tire model to calculate the energy dissipation in a free-rolling aircraft tire and temperature buildup in the tire carcass. The model will provide a means of calculating the influence of tire design on the distribution of tire temperature. Current focus is on energy loss measurements of aircraft tire material. The feasibility of taking test specimens directly from the tire carcass for measurements of viscoelastic properties was demonstrated. The interaction of temperature and frequency effects on material loss properties was studied. The tire model was extended to calculate the cyclic energy change in a tire during rolling under load. Input data representing the 40 by 14 aircraft tire whose material loss properties were measured are being used.

Tielking, John T.

1988-01-01

276

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.

277

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

278

Properties of hot rolled steels for enamelling  

International Nuclear Information System (INIS)

The results of an investigation of the structure and properties of experimental produced hot rolled steels suitable for enamelling are presented in the paper. Hot rolled steels for enamelling represent a special group of the steels for conventional enamelling. Their quality has to be adapted to the method and conditions of enamelling. Therefore, these steels should meet some specific requirements. In addition to usual investigation of the chemical composition and mechanical properties, microstructure and quality of the steel surface also were investigated. The basic aim was to examine steels capability for enamelling, i. e. steels resistance to the fish scales phenomena, by trial enamelling, as well as quality of the steel - enamel contact surface, to evaluate the binding. Also, the changes of the mechanical properties, especially the yield point, during thermal treatment, as a very specific requirement, were investigated, by simplified method. Good results were obtained confirming the steels capability for enamelling. (Original)

279

Analytical inverse solution for coupled thermoelastic problem for the evaluation of contact stress during steel strip rolling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Knowledge of the contact stress between roll and strip is a critical factor in modern, high-speed rolling mills. Previously two inverse analytical methods have been developed to determine the elastic contact stress on the one hand and the heat flux or the temperature in the whole roll (and especially at the surface) on the other hand, by measuring the stress tensor inside the roll body with fibre optics and by measuring the temperature with a thermocouple fully embedded at only one point insi...

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

2013-01-01

280

Missile rolling tail brake torque system  

Science.gov (United States)

Apparatus for simulating varying levels of friction in the bearings of a free rolling tail afterbody on a canard-controlled missile to determine friction effects on aerodynamic control characteristics is described. A ring located between the missile body and the afterbody is utilized in a servo system to create varying levels of friction between the missile body and the afterbody to simulate bearing friction.

Davis, W. T.

1984-01-01

 
 
 
 
281

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

282

Thin layer flow in rolling element bearings  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To extend the service life of rolling element bearings lubricant such as oil or grease is used. In the lubricated contacts between the rollers and the raceways pressures of several GPa can occur. In that case the elastic deformation of the rollers and the raceways has a significant effect on the film thickness and shape. Such contacts are referred to as Elasto-Hydrodynamically Lubricated (EHL) contacts. When the thickness of the lubricant film in an EHL contact is reduced due to insuffici...

Zoelen, Marco Theodorus

2009-01-01

283

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

284

Modeling of Rolling Knee Biped Robot  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2013-01-01

285

Influence of Surge on Extreme Roll Amplitudes  

DEFF Research Database (Denmark)

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

Vidic-Perunovic, Jelena; Pedersen, Preben Terndrup

2008-01-01

286

Compaction Behavior of Isomalt after Roll Compaction  

Directory of Open Access Journals (Sweden)

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

Peter Kleinebudde

2012-09-01

287

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

Science.gov (United States)

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

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

2010-06-01

288

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

289

Troll, a Language for specifying Dice-rolls  

DEFF Research Database (Denmark)

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

Mogensen, Torben Ægidius

2009-01-01

290

Rolling friction—models and experiment. An undergraduate student project  

Science.gov (United States)

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

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

2014-09-01

291

Rolls-Royce digital Rod Control System  

International Nuclear Information System (INIS)

Full text of publication follows: Rolls-Royce has developed a new generation of Rod Control System, based on 40 years of experience. The fifth-generation Rod Control System (RCS) from Rolls-Royce offers a reliable, modular design with adaptability to your preferred platform, for modernization projects or new reactors. Flexible implementation provides the option for you to keep existing cabinets, which permits you to optimize installation approach. Main features for the power part: - Control Rod Drive Mechanism (CRDM) type: 3-coil. - Independent control of each sub-bank. - Each sub-bank is controlled by a cycler unit and 3 identical power racks, each including 4 identical power modules and a common power-supply module. - Coil-per-coil digital control: each power module embeds power-conversion, current-control, and current-monitoring functions for one coil. Control and monitoring are carried out by separate electronics in the module. Current is digitized and fully monitored by means of min-max templates. - A double-hold function is included: a power module assigned to a gripper will activate its coil if a fault risking to cause a reactor trip occurs. - Power modules are standardized, hot-pluggable and self-configured: a power module includes a set of parameters for each type of coil SG, MG, LC. The module recognizes the rack it is plugged in, and chooses automatically parameters to be used. Main benefits: - Reduced operational, maintenance, training, and inventory 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)

292

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

Science.gov (United States)

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

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

2014-11-01

293

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

Directory of Open Access Journals (Sweden)

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

Juliana de Paula Martins

2012-02-01

294

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

Scientific Electronic Library Online (English)

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

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

295

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

Science.gov (United States)

We demonstrate continuous roll-to-roll production of highly conductive silver network films on a plastic substrate via mechanical and chemical welding processes. This process included three essential steps: (i) solvent spraying, (ii) roll compression, and (iii) salt treatment and washing. The sheet resistance of the resulting AgNW film was 5 ? sq(-1) at 92% transmittance, which was the lowest sheet resistance and the highest transparency among the values reported previously for solution-processed AgNW electrodes. Moreover, the strong contacts among the AgNWs dramatically enhanced the mechanical stability of the network film. The resulting AgNW film was successfully applied to various organic electronic devices, such as organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs), and organic solar cells (OSCs). PMID:25169643

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

2014-10-21

296

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

DEFF Research Database (Denmark)

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

Bundgaard, Eva; Hagemann, Ole

2011-01-01

297

Microstructure and temperature monitoring during the hot rolling of AZ31  

Science.gov (United States)

This study details the microstructural evolution during hot rolling of AZ31 alloy sheet using a pilot-scale rolling mill. The aim is to understand the deformation mechanisms leading to grain refinement under industrial processing conditions and to design and optimize the hot rolling schedule for AZ31 in order to produce sheet with a fine and homogeneous microstructure. The study examined three different hot rolling temperatures, 350, 400, and 450°C, and two rolling speeds, 20 and 50 rpm. A total thickness reduction of 67% was obtained using multiple passes, with reductions of either 15% or 30% per pass. It was found that the microstructure of the AZ31 alloy was sensitive to the rolling temperature, the reduction (i.e., strain) per pass and the rolling speed (i.e., strain rate). The results show that the large cast grain structure is broken down by segmentation of the cast grain through localized deformation in twin bands, where dynamic recrystallization occurs in these bands as well as at the grain boundaries (necklacing).

Essadiqi, E.; Shehata, M. T.; Javaid, A.; Galvani, C.; Shen, G.; Yue, S.; Verma, R.

2009-08-01

298

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

Science.gov (United States)

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

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

2014-09-01

299

Large-area roll-to-roll and roll-to-plate nanoimprint lithography: a step toward high-throughput application of continuous nanoimprinting.  

Science.gov (United States)

A continuous roll-to-roll nanoimprint lithography (R2RNIL) technique can provide a solution for high-speed large-area nanoscale patterning with greatly improved throughput; furthermore, it can overcome the challenges faced by conventional NIL in maintaining pressure uniformity and successful demolding in large-area imprinting. In this work, we demonstrate large-area (4 in. wide) continuous imprinting of nanogratings by using a newly developed apparatus capable of roll-to-roll imprinting (R2RNIL) on flexible web and roll-to-plate imprinting (R2PNIL) on rigid substrate. The 300 nm line width grating patterns are continuously transferred on either glass substrate (roll-to-plate mode) or flexible plastic substrate (roll-to-roll mode) with greatly enhanced throughput. In addition, the film thickness after the imprinting process, which is critical in optical applications, as a function of several imprinting parameters such as roller pressure and speed, is thoroughly investigated, and an analytical model has been developed to predict the residual layer thickness in dynamic R2RNIL process. PMID:19702323

Ahn, Se Hyun; Guo, L Jay

2009-08-25

300

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

 
 
 
 
301

Changes of texture and mechanical properties in sheet thickness for rolled low-alloy chromium  

International Nuclear Information System (INIS)

Distribution of texture and mechanical properties by sheet thickness of low-alloy of Cr-V-Y-B system rolled in the 700-1100 deg C temperature range with total 75-80% reduction has been investigated. Methods of pole figures, electron microscopy measurements of microhardness and bend test have been applied. Subsurface hardened layer with increased temperature of cold brittleness and a layer with anomalous crystallographical texture have been disclosed. Reduction of rolling temperature is shown to increase width of the embrittled layer. Formation of subsurface layers is associated with existence of the zone of difficult deformation in the point of contact with rolls of the rolling mill. Strong effect on hardening is produced by boron redistribution with growth of segregation near crystal defects

302

Measurement system of the transverse temperature profile of hot rolled strip  

International Nuclear Information System (INIS)

Output and cost efficiency in the production of hot-rolled strip depend to a large content on the uniformity of geometric and mechanical properties over the length and width of the rolled end product. To ensure the homogeneous temperatures required for this during the rolling process a system to measure and evaluate the transverse temperature profile was developed and implemented in production. The systems used consist of temperature scanners and computers for measurement and data evaluation. The systems have been installed in Kwangyang hot strip mills, in the cases at the exit of the finishing train and at the entry of the coiler. They are used in production to determine the effect of the finishing train and the cooling zone on the technological properties of the hot rolled strip

303

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

304

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

International Nuclear Information System (INIS)

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

305

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

Science.gov (United States)

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

Dumond, Jarrett J.; Ansari Mahabadi, Kambiz; Sok Yee, Yew; Tan, Christina; Hsi Fuh, Jerry Ying; Pueh Lee, Heow; Low, Hong Yee

2012-12-01

306

Estimation of Parametric Roll in a Stochastic Seaway  

DEFF Research Database (Denmark)

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

Jensen, JØrgen Juncher; Pedersen, Preben Terndrup

2008-01-01

307

Strip casting with fluxing agent applied to casting roll  

Science.gov (United States)

A strip caster for producing a continuous strip includes a tundish for containing a melt, a pair of horizontally disposed water cooled casting rolls and devices for electrostatically coating the outer peripheral chill surfaces of the casting rolls with a powder flux material. The casting rolls are juxtaposed relative to one another for forming a pouting basin for receiving the melt through a teeming tube thereby establishing a meniscus 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 to a sealing chamber. A preferred flux is boron oxide having a melting point of about 550 C. The flux coating enhances wetting of the steel melt to the casting roll and dissolves any metal oxide formed on the roll. 3 figs.

Williams, R.S.; O`Malley, R.J.; Sussman, R.C.

1997-07-29

308

The Theory and Technique of Yamuna Body Rolling  

Science.gov (United States)

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

Suzuki, Satoshi

2013-01-01

309

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

310

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

311

On Fail-Rolle polynomials with few roots  

Directory of Open Access Journals (Sweden)

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

L. H. Gallardo

2010-02-01

312

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

313

Three-dimensional finite element modeling of rolling contact fatigue  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Rolling contact fatigue is a stochastic mode of material failure experienced in tribological machine components such as rolling element bearings. The fatigue lives of effected components are significantly dispersed on account of the interaction of highly localized contact loading with heterogeneous microstructure features. Contact conditions often warrant the use of two-dimensional simplifications of the applied loading in investigations of rolling contact fatigue. However, finite three-di...

Weinzapfel, Nicholas J.

2012-01-01

314

Ledelsens rolle i implementeringen af folkeskolereformen  

DEFF Research Database (Denmark)

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

Conrad, Torsten

2014-01-01

315

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

316

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

317

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

318

Description of adult rolling movements and hypothesis of developmental sequences.  

Science.gov (United States)

Physical therapists frequently evaluate and teach patients to roll from a supine to a prone position. The purposes of this study were 1) to describe the rolling movements of adults and 2) to determine whether the movement patterns used to roll might represent different developmental steps within three body regions. Thirty-six healthy adult subjects were videotaped during 10 trials of rolling from a supine to a prone position. Written descriptions of each subject's movements were reduced to general categorical descriptions of movement patterns for three body regions (upper extremities, lower extremities, and head and trunk). Stage theory criteria were used in an attempt to order the movement patterns into developmental sequences. The most common combination of movement patterns was used to describe adults' rolling action. Although stage theory criteria were not met, developmental sequences of movement patterns were proposed for the three body regions. Subjects were quite variable in their rolling movements. The most common form of rolling occurred in less than 12% of the subjects' trials. The descriptions of adults' rolling action gathered in this study provide physical therapists with a variety of movement patterns for teaching patients to roll. PMID:2911618

Richter, R R; VanSant, A F; Newton, R A

1989-01-01

319

Roll bonding steps of 6061 aluminum alloy plates during hot rolling of nuclear fuel plates  

International Nuclear Information System (INIS)

Roll Bonding process is applied to clad the core plate (U3O8+Al), with high strength aluminum alloys during fabrication of plate type nuclear fuel elements for research reactors, and to produce many new constructions which have special uses in industrial applications. In the present work, the steps of the hot roll bonding process were studied using both microscopic examination and mechanical testing. It was found that, there is a threshold of reduction, at which the metallic bond initiates. After this point, the increasing of degree of reduction leads to increase in the bond strength. This reduction threshold was found to be 30%. The final bond strength was about 0.87 of the strength of the base 6061 aluminum alloy at the same conditions of hot working and thermal treatments. The present results showed that at least 81% reduction in thickness is required to produce the required bond between the cladding and both core plate and frame for roll bonded plates with the standard roll bonding method. (author)

320

Twinning, dynamic recovery and recrystallization in the hot rolling process of twin-roll cast AZ31B alloy  

International Nuclear Information System (INIS)

Highlights: ? Two different types of twinning, {101-bar 2} and {101-bar 1}, occurred in the rolling process, and {101-bar 1} twins tended to be preferred sites for recrystallization. ? DRV and discontinuous recrystallization dominated at moderate strain in the rolling process. ? Non-basal slip was homogeneously activated at even larger strains and continuous DRX readily took place on the basis of cellular structures. - Abstract: Hot-rolling experiments with a reduction from 10% to 60% in single pass were conducted on AZ31B twin-roll cast sheets. Optical microscope (OM), electron backscattered diffraction (EBSD) tests and transmission electron microscope (TEM) were used to investigate twinning and DRV/DRX behaviors at different stage in the hot-rolling process. Two types of twinning occurred in the initial stage of hot-rolling process. DRV and discontinuous recrystallization dominated at moderate strain while continuous DRX took place homogeneously throughout original grains at the largest strains.

 
 
 
 
321

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

322

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

International Nuclear Information System (INIS)

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

323

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

324

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

325

Structure inhomogeneity of rolled textured niobium  

International Nuclear Information System (INIS)

The use of a position-sensitive detector in X-ray texture measurements, applied to a cold-rolled Nb foil, allowed to construct the pole figures for various parameters of X-ray line profile, among which there are integral intensity, physical broadening and peak position, as well as the pole figures for the rate of intensity recovery. The distribution of residual deformation effects in the textured material is characterized by an extreme inhomogeneity, manifesting itself by an increase of physical broadening and the recovery rate as the crystallographic orientation of the reflecting grains moves from a texture maximum to a neighbouring texture minimum. The distributions of peak positions exhibit a cross-wise arrangement, where quadrants of predominant extension alternate with quadrants of predominant contraction, resulting in the mutual balance of extending and contracting elastic microstresses. The observed variations of physical broadening and peak position correspond to the whole range of possible deformation effects within the rolled metal, testifying its composite structure. A number of models are proposed to explain the development of structure inhomogeneity in deformed polycrystals. (orig.)

326

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

327

Air friction and rolling resistance during cycling.  

Science.gov (United States)

To calculate the power output during actual cycling, the air friction force Fa and rolling resistance Fr have to be known. Instead of wind tunnel experiments or towing experiments at steady speed, in this study these friction forces were measured by coasting down experiments. Towing experiments at constant acceleration (increasing velocity) were also done for comparison. From the equation of motion, the velocity-time curve v(t) was obtained. Curve-fitting procedures on experimental data of the velocity v yielded values of the rolling resistance force Fr and of the air friction coefficient k = Fa/v2. For the coasting down experiments, the group mean values per body mass m (N = 7) were km = k/m = (2.15 +/- 0.32) x 10(-3)m-1 and ar = Fr/m = (3.76 +/- 0.18) x 10(-2)ms-2, close to other values from the literature. The curves in the phase plane (velocity vs acceleration) and the small residual sum of squares indicated the validity of the theory. The towing experiments were not congruent with the coasting down experiments. Higher values of the air friction were found, probably due to turbulence of the air. PMID:7564978

de Groot, G; Sargeant, A; Geysel, J

1995-07-01

328

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.

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

2007-03-01

329

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 (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

330

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

331

High-precision thickness setting models for titanium alloy plate cold rolling without tension  

Science.gov (United States)

Due to its highly favorable physical and chemical properties, titanium and titanium alloy are widely used in a variety of industries. Because of the low output of a single batch, plate cold rolling without tension is the most common rolling production method for titanium alloy. This method is lack of on-line thickness closed-loop control, with carefully thickness setting models for precision. A set of high-precision thickness setting models are proposed to suit the production method. Because of frequent variations in rolling specification, a model structural for the combination of analytical models and statistical models is adopted to replace the traditional self-learning method. The deformation resistance and friction factor, the primary factors which affect model precision, are considered as the objectives of statistical modeling. Firstly, the coefficient fitting of deformation resistance analytical model based on over-determined equations set is adopted. Additionally, a support vector machine(SVM) is applied to the modeling of the deformation resistance and friction factor. The setting models are applied to a 1450 plate-coiling mill for titanium alloy plate rolling, and then thickness precision is found consistently to be within 3%, exceeding the precision of traditional setting models with a self-learning method based on a large number of stable rolling data. Excellent application performance is obtained. The proposed research provides a set of high-precision thickness setting models which are well adapted to the characteristics of titanium alloy plate cold rolling without tension.

Wang, Xiaochen; Yang, Quan; He, Fei; Sun, Youzhao; Xiao, Huifang

2014-10-01

332

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

333

46 CFR 28.575 - Severe wind and roll.  

Science.gov (United States)

...subjected to the gust wind heeling arm and the angle of roll to windward as specified in this section. (b) The gust wind heeling...vessel, in pounds (Newtons). (c) The angle of roll to windward, A1 , is measured from the equilibrium angle, Ael...

2010-10-01

334

14 CFR 25.491 - Taxi, takeoff and landing roll.  

Science.gov (United States)

...Aeronautics and Space 1 2010-01-01 2010-01-01 false Taxi, takeoff and landing roll. 25.491 Section 25.491 ...CATEGORY AIRPLANES Structure Ground Loads § 25.491 Taxi, takeoff and landing roll. Within the range of...

2010-01-01

335

High speed twin roll casters for aluminum alloy strips  

Energy Technology Data Exchange (ETDEWEB)

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

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

2002-07-01

336

On an extension of Rolle's theorem to locally convex spaces  

Science.gov (United States)

This work concerns the extension of a weak form of the Rolle's theorem to locally convex spaces that satisfy an axiom of separation. The result provides a condition for asserting the uniqueness of a solution to nonlinear functional equations, including nonlinear integro-differential equations. We use the extended Rolle's theorem to prove the uniqueness of a solution to a nonlinear, fractional differential equation.

Kobayashi, Marcelo H.

2006-11-01

337

24 CFR 990.180 - Utilities expense level: Computation of the rolling base consumption level.  

Science.gov (United States)

...level: Computation of the rolling base consumption level. 990.180 Section 990...level: Computation of the rolling base consumption level. (a) General. (1) The rolling base consumption level (RBCL) shall be equal to...

2010-04-01

338

26 CFR 1.263(e)-1 - Expenditures in connection with certain railroad rolling stock.  

Science.gov (United States)

...connection with certain railroad rolling stock. 1.263(e)-1 Section 1.263...connection with certain railroad rolling stock. (a) Allowance of deduction ...rehabilitation of a unit of railroad rolling stock (as defined in paragraph...

2010-04-01

339

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

International Nuclear Information System (INIS)

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

340

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

Science.gov (United States)

...Airworthiness Directives; Rolls-Royce plc Turbofan Engines AGENCY: Federal Aviation...directive (AD) for certain Rolls-Royce plc (RR) RB211-Trent 900 series turbofan...identified in this AD, contact Rolls-Royce plc, Corporate Communications,...

2012-12-10

 
 
 
 
341

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

Directory of Open Access Journals (Sweden)

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

H. Dyja

2014-10-01

342

Cold-rolled steel strip X-ray thickness gauge  

International Nuclear Information System (INIS)

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

343

Truck Roll Stability Data Collection and Analysis  

Energy Technology Data Exchange (ETDEWEB)

The principal objective of this project was to collect and analyze vehicle and highway data that are relevant to the problem of truck rollover crashes, and in particular to the subset of rollover crashes that are caused by the driver error of entering a curve at a speed too great to allow safe completion of the turn. The data are of two sorts--vehicle dynamic performance data, and highway geometry data as revealed by vehicle behavior in normal driving. Vehicle dynamic performance data are relevant because the roll stability of a tractor trailer depends both on inherent physical characteristics of the vehicle and on the weight and distribution of the particular cargo that is being carried. Highway geometric data are relevant because the set of crashes of primary interest to this study are caused by lateral acceleration demand in a curve that exceeds the instantaneous roll stability of the vehicle. An analysis of data quality requires an evaluation of the equipment used to collect the data because the reliability and accuracy of both the equipment and the data could profoundly affect the safety of the driver and other highway users. Therefore, a concomitant objective was an evaluation of the performance of the set of data-collection equipment on the truck and trailer. The objective concerning evaluation of the equipment was accomplished, but the results were not entirely positive. Significant engineering apparently remains to be done before a reliable system can be fielded. Problems were identified with the trailer to tractor fiber optic connector used for this test. In an over-the-road environment, the communication between the trailer instrumentation and the tractor must be dependable. In addition, the computer in the truck must be able to withstand the rigors of the road. The major objective--data collection and analysis--was also accomplished. Using data collected by instruments on the truck, a ''bad-curve'' database can be generated. Using this database, instrumented vehicles would not need roadside beacons. The speed, acceleration, and roll stability of the vehicle could be determined prior to entering a curve, and a warning issued, if appropriate, for curves that have been characterized in the database. Thus, the analysis indicates that the data can be effectively used to provide a timely warning of rollover risk.

Stevens, SS

2001-07-02

344

Method and apparatus for mechanically classifying rolling bodies  

International Nuclear Information System (INIS)

A bowl feeder for separating damaged rolling bodies, for example nuclear fuel pellets, from sound ones includes a bowl having a central conical section for distributing the bodies radially outwardly towards a V-shaped circular channel which ensures that the bodies are arranged end-to-end with the rolling axes orientated lengthwise of the channel. The channel discharges the bodies onto an outer sloping section to allow bodies with asymmetrical defects to resist rolling while allowing defect free bodies to roll radially outwardly down the slope. A system of rails with gaps serves to separate defective bodies from those which are defect free, the latter being allowed to roll to the outer periphery of the bowl and eventually to feed track while the former are routed to a reject outlet. (author)

345

Development of rolling texture in copper and brass  

DEFF Research Database (Denmark)

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

Leffers, Torben

1968-01-01

346

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

347

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

DEFF Research Database (Denmark)

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

Krebs, Frederik C; Norrman, Kion

2010-01-01

348

Quality control of roll-to-roll processed polymer solar modules by complementary imaging methods  

DEFF Research Database (Denmark)

We applied complementary imaging methods to investigate processing failures of roll-to-roll solution processed polymer solar modules based on polymer:fullerene bulk heterojunctions. For investigation of processing deficiencies in solar modules we employed dark lock-in thermography (DLIT), electroluminescence (ELI) and photoluminescence/reflection imaging (PLI/RI) complemented by optical imaging (OI). The combination of all high resolution images allowed us to allocate the origin of processing errors to a specific deposition process, i.e. the insufficient coverage of an electrode interlayer. The investigation can be divided into a fast DLIT overview of the module and a successive more detailed analysis of the suspicious region by all imaging methods.

Rösch, R.; Krebs, Frederik C

2012-01-01

349

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

DEFF Research Database (Denmark)

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

Larsen-Olsen, Thue Trofod; Andersen, Thomas Rieks

2012-01-01

350

Roll-to-roll anodization and etching of aluminum foils for high-throughput surface nanotexturing.  

Science.gov (United States)

A high-throughput process for nanotexturing of hard and soft surfaces based on the roll-to-roll anodization and etching of low-cost aluminum foils is presented. The process enables the precise control of surface topography, feature size, and shape over large areas thereby presenting a highly versatile platform for fabricating substrates with user-defined, functional performance. Specifically, the optical and surface wetting properties of the foil substrates were systematically characterized and tuned through the modulation of the surface texture. In addition, textured aluminum foils with pore and bowl surface features were used as zeptoliter reaction vessels for the well-controlled synthesis of inorganic, organic, and plasmonic nanomaterials, demonstrating yet another powerful potential use of the presented approach. PMID:21774501

Lee, Min Hyung; Lim, Namsoo; Ruebusch, Daniel J; Jamshidi, Arash; Kapadia, Rehan; Lee, Rebecca; Seok, Tae Joon; Takei, Kuniharu; Cho, Kee Young; Fan, Zhiyoung; Jang, Hwanung; Wu, Ming; Cho, Gyoujin; Javey, Ali

2011-08-10

351

Bimaterial composites via colloidal rolling techniques. 1: Microstructure evolution during rolling  

International Nuclear Information System (INIS)

Laminate composites of Al2O3 and ZrO2 fabricated by repeated rolling and folding are demonstrated using aqueous slurries of ceramic powders without any plasticizers or binders. Crack-free composites with a layer thickness of 4--60 microm have been obtained. A novel interface instability during the rolling of bimaterial slurries, which leads to the entrapment of the rheologically harder phase in the softer phase, also has been discovered. This discovery has been exploited to obtain layered materials, by matching the yield stress of the slurries, or cellular materials with the desired included phase, by mismatching the yield stress of the slurries. Adjustment of the yield stress can be realized by varying only the NH4NO3 salt concentration while keeping the pH and the solids loading (64 vol%) constant

352

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

353

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

DEFF Research Database (Denmark)

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

SØndergaard, Roar R.; Hösel, Markus

2013-01-01

354

Rolling element fatigue testing of gear materials  

Science.gov (United States)

Rolling element fatigue lives of eleven alloys were evaluated. The eleven alloys studied were three nitriding alloys (Super Nitralloy, Nitralloy 135, and Nitralloy N), four case carburizing alloys (AISI 9310, CBS 600, CBS 1000M and Vasco X-2), and four throughhardening alloys (Vasco Matrix II,AISI W-1, AISI S-2 and AISI O-2). Several different heat treatments and/or melting processes were studied on the three carburizing alloy steels. Metallurgical analyses were made before and after the RC rig tests. Test data were statistically analyzed using the Weibull distribution function. B-10 lives were compared versus VIM-VAR AISI M-50 and carburized VAR AISI 9310, as reference alloys.

Nahm, A. H.

1978-01-01

355

Inhomogeneous Fragmentation of the Rolling Tachyon  

CERN Document Server

Dirac-Born-Infeld type effective actions reproduce many aspects of string theory classical tachyon dynamics of unstable Dp-branes. The inhomogeneous tachyon field rolling from the top of its potential forms topological defects of lower codimensions. In between them, as we show, the tachyon energy density fragments into a p-dimensional web-like high density network evolving with time. We present an analytic asymptotic series solution of the non-linear equations for the inhomogeneous tachyon and its stress energy. The generic solution for a tachyon field with a runaway potential in arbitrary dimensions is described by the free streaming of noninteracting massive particles whose initial velocities are defined by the gradients of the initial tachyon profile. Thus, relativistic particle mechanics is a dual picture of the tachyon field effective action. Implications of this picture for inflationary models with a decaying tachyon field are discussed.

Felder, G N; Felder, Gary N.; Kofman, Lev

2004-01-01

356

Thermodynamic interpretation of time for rolling tachyons  

International Nuclear Information System (INIS)

We show that the open string worldsheet description of brane decay (discussing a specific example of a rolling tachyon background) can be related to a sequence of points of thermodynamic equilibrium of a grand canonical ensemble of point charges on a circle, the Dyson gas. Subsequent instants of time are related to neighboring values of the chemical potential or the average particle number N. The free energy of the system decreases in the direction of larger N or later times, thus defining a thermodynamic arrow of time. Time evolution equations are mapped to differential equations relating thermal expectation values of certain observables at different points of thermal equilibrium. This suggests some lessons concerning emergence of time from an underlying microscopic structure in which the concept of time is absent

357

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

Science.gov (United States)

...71 Terminals handling intermodal containers or roll-on roll-off...operations. (a) Every intermodal container shall be legibly...ii) of this section or by shipping documents. (8) Any scale...section, unless damage to an intermodal container makes special...

2010-07-01

358

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...hot-rolled steel from Brazil and Japan, and the suspended antidumping...hot-rolled steel from Brazil and Japan, and/ or the suspended investigation...the Commission's Rules of Practice and Procedure, part 201...reviews. Limited disclosure of business proprietary information...

2010-10-12

359

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

Science.gov (United States)

...Carbon-Quality Steel Products From Brazil, Japan, and Russia AGENCY: United States International...on hot-rolled steel from Brazil and Japan, and the suspended investigation on...on hot-rolled steel from Brazil and Japan, and the suspended investigation on...consult the Commission's Rules of Practice and Procedure, part 201, subparts...

2010-07-22

360

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

DEFF Research Database (Denmark)

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

Spyropoulos, G. D.; Kubis, P.

2014-01-01

 
 
 
 
361

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

362

40 CFR 426.30 - Applicability; description of the rolled glass manufacturing subcategory.  

Science.gov (United States)

...AND STANDARDS GLASS MANUFACTURING POINT SOURCE CATEGORY Rolled Glass Manufacturing Subcategory § 426...description of the rolled glass manufacturing subcategory. The...ingredients (sand, soda ash, limestone,...

2010-07-01

363

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

364

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

365

Design, Analysis and Optimization of Anti-Roll Bar  

Directory of Open Access Journals (Sweden)

Full Text Available Vehicle anti-roll bar is part of an automobile suspension system which limits body roll angle. This U-shaped metal bar connects opposite wheels together through short lever arms and is clamped to the vehicle chassis with rubber bushes. Its function is to reduce body roll while cornering, also while travelling on uneven road which enhances safety and comfort during driving. Design changes of anti-roll bars are quite common at various steps of vehicle production and a design analysis must be performed for each change. So Finite Element Analysis (FEA can be effectively used in design analysis of anti-roll bars. The finite element analysis is performed by ANSYS. This paper includes pre-processing, analysis, post processing, and analyzing the FEA results by using APDL (Ansys Parametric Design Language. The effects of anti-roll bar design parameters on final anti-roll bar properties are also evaluated by performing sample analyses with the FEA program developed in this project.

Pravin Bharane

2014-09-01

366

Determining asymmetry of roll-over shapes in prosthetic walking  

Directory of Open Access Journals (Sweden)

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

Carolin Curtze, MSc

2011-12-01

367

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

368

Clad strip casting by a twin roll caster  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

2009-01-01

369

Analysis of slug flow unit model in rolling vertical tube  

International Nuclear Information System (INIS)

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

370

Surface temperature measurements in rolling and sliding EHD contacts  

Science.gov (United States)

In this study, moving surface temperature measurements in rolling and sliding EHD point contacts were made using an available infrared technique. Film thickness and traction have also been measured. Slide-to-roll ratios of -2 to +2 have been studied. By using a different kinematic configuration, stationary surface temperatures have also been measured. It has been shown that, while surface temperature rises in the low slip region are relatively small, stationary surface temperatures are significantly higher than the moving surface temperatures. Flash temperature theory has been extended to cover the combined rolling and sliding conditions. Correlation between the predicted and the measured values has also been performed.

Nagaraj, H. S.; Sanborn, D. M.; Winer, W. O.

1978-01-01

371

Microstructural evolution of hot and cold rolled Al-based particulate-reinforced composites  

International Nuclear Information System (INIS)

Hot and cold formability of Al-based particulate-reinforced composites was investigated. A 2618/20%SiC and 6061/20%Al2O3 composite, as well as a 6061 unreinforced alloy were subjected to hot rolling on laboratory mills to reduce the starting bars to sheets with a thickness of 4 mm. Cold rolling was then performed to produce thin tapes and wires with several deformation levels, up to 90%. The obtained materials were then tested to investigate the evolution of microhardness and mechanical properties. The present work was also aimed at studying in detail the evolution of microstructure and of the aging behaviour of the composites as a function of their fabrication condition. In particular, the effects of extensive workhardening induced during cold rolling are considered. Moreover, DSC analyses were carried out to study the aging and recrystallisation behaviour of the deformed samples. (author)

372

A new model for the prediction of the steepness profile across the strip in flat rolling  

Science.gov (United States)

In flat rolling, wavy surfaces are easily formed in the strip, causing the problem of poor flatness. The wavy surfaces may not only reduce the commercial value of the product but also lead to the breakage of the strip while passing through the roll gap. Therefore, it is necessary to strictly control the wave formation. In this paper, we present a new approach to the prediction of the wavy shape of the strip. The approach is based on minimization of the potential energy and adopts Ritz method as a solution technique. The approach is described in detail, with emphasis on the procedure to treat the effect of the total tension on the shape of the formed waves. The prediction accuracy of the proposed model is examined through comparison with predictions from the finite element method. Then, demonstrated is the model's capability of reproducing various wavy surfaces that may be observed in the flat rolling mill.

Kim, Jinseok; Hwang, Sangmoo

2010-06-01

373

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

374

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

Science.gov (United States)

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

Ghosh, S. K.

2014-10-01

375

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

376

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.

377

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

DEFF Research Database (Denmark)

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

Carlé, Jon Eggert

2013-01-01

378

Rolling contact fatigue testing of thermally sprayed coatings  

International Nuclear Information System (INIS)

Two Rolling Contact Fatigue (RCF) test systems have been developed in order to compare coatings according to their service lives under high-load rolling contact. Experimental testing facilities of the three-roller and the two-roller type RCF test equipment are presented and problems involved with testing of thermally sprayed coatings are discussed. The aim of this three-year-project is to study reasons for development of coating micropitting and delamination of high-velocity oxyfuel (HVOF) and detonation gun sprayed coatings. Some observations of rolling contact fatigue behavior of detonation gun sprayed WC+12% Co coating subjected to a nearly pure rolling line contact at cyclic Hertzian stress level of approximately 410 MPa are made, but interpreting the results requires still more work

379

Cold rolling textures in AZ31 wrought magnesium alloy  

International Nuclear Information System (INIS)

Samples of the magnesium alloy AZ31 (3 wt% Al, 1 wt% Zn, balance Mg) with two microstructures, recrystallized and squeeze cast, were rolled at room temperature. The initial texture and the final cold rolling texture were investigated by X-ray diffraction. The cold rolling texture of both examined initial microstructures consists of two fibres, representing the familiar double peak in the basal pole tilted ±15 deg. from the normal direction to the rolling direction. A systematic texture modelling was performed using a viscoplastic Taylor model, based on different combinations of four slip modes and one twinning mode. The best agreement with experiment can be achieved for a combination of -basal, -prismatic, -pyramidal slip systems together with the {0 1 1-bar 2} twinning system

380

Cold rolling textures in AZ31 wrought magnesium alloy  

Energy Technology Data Exchange (ETDEWEB)

Samples of the magnesium alloy AZ31 (3 wt% Al, 1 wt% Zn, balance Mg) with two microstructures, recrystallized and squeeze cast, were rolled at room temperature. The initial texture and the final cold rolling texture were investigated by X-ray diffraction. The cold rolling texture of both examined initial microstructures consists of two fibres, representing the familiar double peak in the basal pole tilted {+-}15 deg. from the normal direction to the rolling direction. A systematic texture modelling was performed using a viscoplastic Taylor model, based on different combinations of four slip modes and one twinning mode. The best agreement with experiment can be achieved for a combination of -basal, -prismatic, -pyramidal slip systems together with the {l_brace}0 1 1-bar 2{r_brace}<0 1 1-bar 1-bar> twinning system.

Styczynski, A.; Hartig, Ch.; Bohlen, J.; Letzig, D

2004-04-15

 
 
 
 
381

Prediction of Parametric Roll Resonance by Multilayer Perceptron Neural Network  

DEFF Research Database (Denmark)

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

Galeazzi, Roberto; Blanke, Mogens

2011-01-01

382

The condition for classical slow rolling in new inflation  

International Nuclear Information System (INIS)

By means of the stochastic description of inflation, we investigate the dynamics of a fixed comoving domain in a continuously inflating universe on the global scale, both analytically and numerically. A particular attention is paid to the condition for a domain to enter the classical slow rolling phase. New inflationary universe models with the potential form, V(?) ? V0 - c?2n at ? ? 0 are considered. The critical value of the scalar field beyond which the field slowly rolls down the potential hill is estimated. We find, for all models under consideration, the condition for classical slow rolling is a sufficient condition for the expected amplitude of density perturbations to be smaller than unity. In other words, the density perturbation amplitude at the later Friedmann stage is always smaller than unity if the universe experienced the classical slow roll-over phase. (author)

383

Numerical simulations supporting the process design of ring rolling processes  

Science.gov (United States)

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

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

2013-05-01

384

Homogeneous rolling tachyons in boundary string field theory  

International Nuclear Information System (INIS)

We study decay of a flat unstable Dp-brane in the context of boundary string field theory action. Three types of homogeneous rolling tachyons are obtained without and with Born-Infeld type electromagnetic field

385

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

386

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

387

Dynamic Effect of Rolling Massage on Blood Flow  

International Nuclear Information System (INIS)

The Chinese traditional medical massage has been used as a natural therapy to eliminate some diseases. Here, the effect of the rolling massage frequency to the blood flow in the blood vessels under the rolling massage manipulation is studied by the lattice Boltzmann simulation. The simulation results show that when the frequency is smaller than or comparable to the pulsatile frequency of the blood flow, the effect on the blood flux by the rolling massage is small. On the contrast, if the frequency is twice or more times of the pulsatile frequency of the blood flow, the blood flux is greatly enhanced and increases linearly with respect to the frequency. Similar behavior has also been observed on the shear stress on the blood vessel walls. The result is helpful for understanding that the rolling massage has the function of promoting the blood circulation and removing the blood stasis.

388

Reduction of dispersive ground-roll using time delay spectrometry  

DEFF Research Database (Denmark)

Velocity filtering seismic traces requires fulfilment of the sampling theorem in the time domain and in the space domain. Since the latter condition is seldom met in exploration seismics, a method based on ?-p transformation combined with time varying filtering is proposed for solving the problem of reducing dispersive ground-roll in a seismic trace. Although it is possible to mask out ground-roll in the ?-p domain, mapping of the ?-p domain back into the original x-t domain involves numerical difficulties because the used inverse discrete Radon transform is ill-posed. To circumvent this problem the seismic trace is applied to a time varying filter with a stop-band which at any instant corresponds to the instantaneous frequency of the ground-roll, thus reducing the ground-roll with minimum distortion of the wanted seismic rate

Kjeldsen, Peter MØller

1992-01-01

389

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

Directory of Open Access Journals (Sweden)

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

A. Grajcar

2013-03-01

390

The twin-roll casting of magnesium alloys  

Science.gov (United States)

Recently, technologies for twin-roll casting have been widely developed to efficiently fabricate the lightweight Mg alloy sheets that are quite attractive for numerous weight-sensitive applications. This paper reviews the recent progress in the twin-roll casting of Mg alloys, focusing on the processing aspects that have close relations to the solidification behavior of Mg alloy strips. In addition, recent attempts to develop new Mg alloys utilizing the metallurgical advantages attainable by this novel casting process are also presented.

Park, S. S.; Park, W.-J.; Kim, C. H.; You, B. S.; Kim, Nack J.

2009-08-01

391

Light-weight materials produced by accumulative roll bonding  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The work presented in this thesis is an experimental study of roll bonding and accumulative roll bonding of similar and dissimilar metal combinations with special focus on bond strength evaluation, post process heat treatments and layer continuity of the harder phase. Three objectives have been pursued. The first objective was development of a new method to test the bond strength in tensile mode. The second objective was to assess the influence of post deformation heat treatments on the mecha...

Govindaraj, Nagaraj Vinayagam

2013-01-01

392

Dimethylsulfoxide exposure modulates HL-60 cell rolling interactions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ch...

2012-01-01

393

Dimethylsulfoxide exposure modulates HL-60 cell rolling interactions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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–...

Gee, David X. A. J.; Kate Wright, L. X. A.; Jonathan Zimmermann; Kayla Cole; Karen Soule; Michelle Ubowski

2012-01-01

394

Continuous roll casting of aluminium alloys – casting parameters analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2010-01-01

395

Thermal and thermoelastic effects in rolling/sliding contacts  

Science.gov (United States)

This report describes a theoretical and experimental study of thermal and thermomechanical effects on frictionally and electrically heated rolling/sliding surfaces. A 2-D thermal analysis is used to predict the temperature distribution through the thickness of the lubricant film in an elastohydrodynamic (EHD) contact. The relative magnitude of shear and compressive heating as well as the losses due to conduction and convection are compared for pure rolling and slip conditions.

Dow, T. A.; Lawson, D. K.; Sadeghi, F.

1984-09-01

396

Wheel rolling constraints and slip in mobile robots  

Energy Technology Data Exchange (ETDEWEB)

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

Shekhar, S.

1997-03-01

397

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

Science.gov (United States)

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

Salonitis, Konstantinos; Paralikas, John; Chryssolouris, George

398

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)

399

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

International Nuclear Information System (INIS)

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

400

Influence of the GZ calculation method on parametric roll prediction  

DEFF Research Database (Denmark)

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

Vidic-Perunovic, Jelena

2011-01-01

 
 
 
 
401

Rolling in the Higgs Model and Elliptic Functions  

CERN Document Server

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

Arefeva, I Ya; Volovich, I V

2012-01-01

402

Design of tooling for cold rolling of Zry tubes  

International Nuclear Information System (INIS)

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

403

Analysis of leukocyte rolling in vivo and in vitro.  

Science.gov (United States)

Leukocyte rolling is an important step for the successful recruitment of leukocytes from blood to tissues mediated by a specialized group of glycoproteins termed selectins. Because of the dynamic process of leukocyte rolling, binding of selectins to their respective counter-receptors (selectin ligands) needs to fulfill three major requirements: (1) rapid bond formation, (2) high tensile strength, and (3) fast dissociation rates. These criteria are perfectly met by selectins, which interact with specific carbohydrate determinants on selectin ligands. This chapter describes the theoretical background, technical requirements, and analytical tools needed to quantitatively assess leukocyte rolling in vivo and in vitro. For the in vivo setting, intravital microscopy allows the observation and recording of leukocyte rolling under different physiological and pathological conditions in almost every organ. Real-time and off-line analysis tools help to assess geometric, hemodynamic, and rolling parameters. Under in vitro conditions, flow chamber assays such as parallel plate flow chamber systems have been the mainstay to study interactions between leukocytes and adhesion molecules under flow. In this setting, adhesion molecules are immobilized on plastic, in a lipid monolayer, or presented on cultured endothelial cells on the chamber surface. Microflow chambers are available for studying leukocyte adhesion in the context of whole blood and without blood cell isolation. The microscopic observation of leukocyte rolling in different in vivo and in vitro settings has significantly contributed to our understanding of the molecular mechanisms responsible for the stepwise extravasation of leukocytes into inflamed tissues. PMID:17113878

Sperandio, Markus; Pickard, John; Unnikrishnan, Sunil; Acton, Scott T; Ley, Klaus

2006-01-01

404

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

DEFF Research Database (Denmark)

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

Hösel, Markus; Angmo, Dechan

2014-01-01

405

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

Science.gov (United States)

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

Smith, Kevin; Paterson, Eric

2008-11-01

406

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

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

2007-01-01

407

Interlayer adhesion in roll-to-roll processed flexible inverted polymer solar cells  

DEFF Research Database (Denmark)

The interlayer adhesion of roll-to-roll processed flexible inverted P3HT:PCBM bulk heterojunction (BHJ) polymer solar cells is reported. Poor adhesion between adjacent layers may result in loss of device performance from delamination driven by the thermomechanical stresses in the device. We demonstrate how a thin-film adhesion technique can be applied to flexible organic solar cells to obtain quantitative adhesion values. For the P3HT:PCBM-based BHJ polymer solar cells, the interface of the BHJ with the conductive polymer layer PEDOT:PSS was found to be the weakest. The adhesion fracture energy varied from 1.6 J/m2 to 0.1 J/m2 depending on the composition of the P3HT:PCBM layer. Post-deposition annealing time and temperature were shown to increase the adhesion at this interface. Additionally the PEDOT:PSS cells are compared with V2O5 cells whereby adhesive failure marked by high fracture energies was observed.

Krebs, Frederik C

2012-01-01

408

Preorganization of Nanostructured Inks for Roll-to-Roll-Coated Polymer Solar Cells  

DEFF Research Database (Denmark)

The challenges associated with obtaining the desired nanomorphology of the active layer in polymer solar cells were addressed through preparation of conjugated polymer chains grown from the surface of seed nanoparticles with a well-defined size. Poly-3-hexylthiophene (P3HT) was thus polymerized using a quasi-living chain polymerization method initiated by surface-modified silica nanoparticles. The nanoparticles with a silica core and a P3HT-corona exhibited excellent solubility and optical properties similar to native P3HT. Upon mixing with phenyl-C61-butyric acid methyl ester in solution, a preorganized ink was obtained that was used to make polymer solar cell modules in a full roll-to-roll coating and printing process operating in ambient air. The polymer solar cells were thus prepared by a mixture of slot die and flat-bed screen printing. Various polymer solar cell modules were prepared ranging from single cells to two, three, and eight serially connected cells. The power conversion efficiency for the polymer solar cell modules were in the range of 0.8%-1.2% with an active area of up to 120 cm.

Krebs, Frederik C

2010-01-01

409

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.

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

410

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

DEFF Research Database (Denmark)

In this report we employ static and roll-to-roll (R2R) photonic sintering processes on flexo printed silver nanoparticle-based electrode structures with a heat-sensitive 60 mm thin barrier foil as a substrate. We use large area electrode structures to visualize the increased optical footprint of single and quadruple flashes, and the R2R challenges in the form of overlapping exposures. It is shown that single flash exposure is enough to significantly increase the conductivity and adhesion without damaging the foil or build-up of cracks in the silver layer. Additional flash exposures or increased energies above the threshold level have only minor impact on the conductivity but lead to cracks and substrate deformation. A second silver nanoparticle ink was printed, which was already optimized for lowtemperature drying. Here we show that photonic sintering has only a minor impact on the conductivity as the nanoparticles are already sintered. The advantage of single exposure is the ability to produce higher R2R processing speeds without overlapping, which is shown in the form of theoretical calculations.

Hösel, Markus; Krebs, Frederik C

2012-01-01

411

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

412

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

413

A life cycle analysis of polymer solar cell modules prepared using roll-to-roll methods under ambient conditions  

DEFF Research Database (Denmark)

A life cycle analysis was performed on a full roll-to-roll coating procedure used for the manufacture of flexible polymer solar cell modules. The process known as ProcessOne employs a polyester substrate with a sputtered layer of the transparent conductor indium-tin-oxide (ITO). The ITO film was processed into the required pattern using a full roll-to-roll process, employing screen printing of an etch resist and then applying etching, stripping, washing and drying procedures. The three subsequent layers; ZnO, P3HT:PCBM and PEDOT:PSS were slot-die coated and the silver back electrode was screen printed. Finally the polymer solar modules were encapsulated, using a polyester barrier material. All operations except the application of ITO were carried out under ambient conditions. The life cycle analysis delivered a material inventory of the full process for a module production, and an accountability of the energy embedded both in the input materials and in the production processes. Finally, upon assumption of power conversion efficiencies and lifetime for the modules, a calculation of energy pay-back time allowed us to compare this roll-to-roll manufacturing with other organic and hybrid photovoltaic technologies. The results showed that an Energy Pay-Back Time (EPBT) of 2.02 years can be achieved for an organic solar module of 2% efficiency, which could be reduced to 1.35 years, if the efficiency was 3%.

Espinosa Martinez, Nieves; Krebs, Frederik C

2011-01-01

414

Effects of the microstructure of twin roll cast and hot rolled plates on the surface quality of presensitized plates  

Science.gov (United States)

The effect of the microstructure of plates fabricated both in the traditional process, involving casting, hot rolling and cold rolling (HR), and in the novel twin roll casting + cold rolling (TRC) process on the surface quality of presensitized (PS) plates was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDXS). The formation of pores on the surface of the electrolyzed HR plate could be attributed to the presence of approximately 1-?m-sized large Al-Fe precipitates in the HR plate compared to the smaller precipitates in the TRC plate. Moreover, residual graphite lubricants used during the TRC process were entrapped on the surface of the TRC plate during the subsequent rolling process. The entrapped pollutants tended to further deteriorate the formation of pores on the surface of the TRC plate, and no residual carbon was detected on the surface of the HR plate. Furthermore, the surface quality of the TRC plate can be improved by surface cleaning before the cold rolling process, which could dramatically lower the residual graphite on the surface.

Zhu, Yuan-Zhi; Zhang, Ya-Feng; Zhao, Chao-Qi; Zhou, Feng

2014-09-01

415

Continuous roll-to-roll amorphous silicon photovoltaic manufacturing technology. Semiannual subcontract report, 1 April 1993--30 September 1993  

Energy Technology Data Exchange (ETDEWEB)

This report describes work for this reporting period under a 3-year program to advance Energy Conversion Device`s (ECD) roll-to-roll, triple-junction photovoltaic (PV) manufacturing technologies, to reduce the module production costs, to increase the stabilized module performance, and to expand commercial production capacity utilizing ECD technology. The specific 3-year goal is to develop advanced large-scale manufacturing technology incorporating ECD`s earlier research advances with the capability of producing modules with stable 11% efficiency at a cost of approximately $1.00 per peak watt. Major accomplishments during this reporting period include (1) the design, construction. amd testomg of a continuous roll-to-roll multipurpose amorphous silicon alloy solar cell deposition machine that incorporates improvements necessary to obtain higher efficiency solar cells; (2) development of a photothermal deflection spectroscopy (PDS) technique for evaluating back-reflector systems; (3) the development of an improved textured Ag/ZnO back-reflector system demonstrating 25% gain in J{sub sc} over previous textured Al back-reflector systems; and (4) the design of a serpentine web continuous roll-to-roll deposition chamber.

Izu, M [Energy Conversion Devices, Inc., Troy, MI (United States)

1994-06-01

416

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

417

75 FR 47541 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products from Brazil and Japan: Final Results of...  

Science.gov (United States)

... Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2010-08-06

418

75 FR 75455 - Certain Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil: Final Results of Full...  

Science.gov (United States)

... Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2010-12-03

419

76 FR 36081 - Hot-Rolled Flat-Rolled Carbon-Quality Steel Products From Brazil and Japan: Revocation of the...  

Science.gov (United States)

... Hot-rolled dual phase steel, phase-hardened, primarily...Hot-rolled bearing quality steel, SAE grade 1050, in coils, with an inclusion rating of 1.0 maximum per...ASTM A570-50 hot-rolled steel sheet in coils or cut...

2011-06-21

420

Optimal control of conditions of deformation during rolling the bar alloy from alloy steel  

International Nuclear Information System (INIS)

A complex of programs for determining the optimal gaps between rollers during rolling of simple merchant sections of alloy steels of a wide brand assortment (12KhN3A, Kh17N2, Kh18N10T) was elaborated. Experience in calculations made according to the programs suggests advisability of their use in the automated design systems for roller calibration and for adjustment of section mills

 
 
 
 
421

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