scholarly journals Control of speed modes of heavy-plate mills rolling.

2021 ◽  
Vol 4 ◽  
pp. 91-98
Author(s):  
M.G. Ievlev ◽  
Keyword(s):  
Rolled Product ◽  
High Speed ◽  
Engine Speed ◽  
Operating Time ◽  
Rolling Process ◽  
Maximum Acceleration ◽  
Heavy Plate ◽  
Thickness Variations ◽  
Technological Limitations ◽  
Rolling Stability

Control of speed modes on heavy-plate mills is one of the factors that determine the efficiency of the rolling process. The choice of speed controls influences the mill productivity, geometric dimensions of the rolled product (longitudinal thickness variations) and compliance with the set temperature mode which determine the mechanical properties of the rolled product, etc. The article considers the limitations in the choice of speed controls which can be divided into two groups: limitations of the capabilities of rolling engines and technological limitations. The first group is determined by the allowable engine under the conditions of reliable current switching on the collector and the maximum allowable engine speed. Technological limitations of speed controls are considered in the paper as well. The speed of grasp is limited to the maximum un-der the condition of metal grasp without skew, blows and dynamic torque overloads in spindles and maintenance of constant grasp without slipping, as well as the possibility of prevention of emergencies. Steady (maximum) rolling speed can be limited to the maximum by the conditions of rolling stability and prevention of sticking of metal to the rolls. The rate of metal release from the rolls is usually chosen in the way so that the pause stipulated by the braking of the sheet on the roller conveyor and its subsequent return to the rolling mill would not exceed the operating time of the pressure mechanism. In some cases, the release rate can be determined by other technological operations. The maximum acceleration of the main drive of the horizontal mill is limited by the conditions of slipping of the working roll towards the sup-port roll. The paper also considers rational speed graphs of rolling on heavy-plate mills. They are the most common type of high-speed rolling graphs on heavy-plate mills. The listed above solutions for the control of high-speed rolling modes can be used in the development of APCS of heavy-plate mills rolling.

Kinematics of Tongue Projection in Chamaeleo Oustaleti

1991 ◽  
Vol 159 (1) ◽  
pp. 109-133 ◽  
Author(s):  
PETER C. WAINWRIGHT ◽  
DAVID M. KRAKLAU ◽  
ALBERT F. BENNETT
Keyword(s):  
High Speed ◽  
Prey Capture ◽  
Maximum Velocity ◽  
Head Movements ◽  
Florida State University ◽  
State University ◽  
Maximum Acceleration ◽  
Related Family ◽  
High Speed Cinematography ◽  
Tongue Movements

The kinematics of prey capture by the chamaeleonid lizard Chamaeleo oustaleti were studied using high-speed cinematography. Three feeding sequences from each of two individuals were analyzed for strike distances of 20 and 35 cm, at 30°C. Ten distances and angles were measured from sequential frames beginning approximately 0.5 s prior to tongue projection and continuing for about 1.0 s. Sixteen additional variables, documenting maximum excursions and the timing of events, were calculated from the kinematic profiles. Quantified descriptions of head, hyoid and tongue movements are presented. Previously unrecognized rapid protraction of the hyobranchial skeleton simultaneously with the onset of tongue projection was documented and it is proposed that this assists the accelerator muscle in powering tongue projection. Acceleration of the tongue occurred in about 20ms, reaching a maximum acceleration of 486 m s−2 and maximum velocity of 5.8m s−1 in 35 cm strikes. Deceleration of the tongue usually began within 5 ms before prey contract and the direction of tongue movement was reversed within 10 ms of prey contact. Retraction of the tongue, caused by shortening of the retractor muscles, reached a maximum velocity of 2.99 ms−1 and was complete 330 ms after prey contact. Projection distance influences many aspects of prey capture kinematics, particularly projection time, tongue retraction time and the extent of gape and head movements during tongue retraction, all of which are smaller in shorter feedings. Though several features of the chameleon strike have apparently been retained from lizards not capable of ballistic tongue projection, key differences are documented. Unlike members of a related family, the Agamidae, C. oustaleti uses no body lunge during prey capture, exhibits gape reduction during tongue projection and strongly depresses the head and jaws during tongue retraction. Note: Present address: Department of Biological Sciences, Florida State University, Tallahassee, FL 32306, USA.

Comparison of the fast-start performances of closely related, morphologically distinct threespine sticklebacks (Gasterosteus spp.)

1996 ◽  
Vol 199 (12) ◽  
pp. 2595-2604 ◽  
Author(s):  
T Law ◽  
R Blake
Keyword(s):  
Angular Velocity ◽  
High Speed ◽  
High Performance ◽  
Gasterosteus Aculeatus ◽  
Morphological Characteristics ◽  
Maximum Velocity ◽  
Threespine Stickleback ◽  
Biomechanical Study ◽  
Maximum Acceleration ◽  
Fast Start

Fast-start escape performances for two species of threespine stickleback, Gasterosteus spp., were investigated using high-speed cinematography (400 Hz). The two fishes (not yet formally described, referred to here as benthic and limnetic) inhabit different niches within Paxton Lake, British Columbia, Canada, and are recent, morphologically distinct species. All escape responses observed for both species were double-bend C-type fast-starts. There were no significant differences between the species for any linear or angular parameter (pooled averages, both species: duration 0.048 s, distance 0.033 m, maximum velocity 1.10 m s-1, maximum acceleration 137 m s-2, maximum horizontal angular velocity 473.6 rad s-1 and maximum overall angular velocity 511.1 rad s-1). Benthics and limnetics have the greatest added mass (Ma) at 0.3 and 0.6 body lengths, respectively. The maximum Ma does not include the fins for benthics, but for limnetics the dorsal and anal fins contribute greatly to the maximum Ma. The deep, posteriorly placed fins of limnetics enable them to have a fast-start performance equivalent to that of the deeper-bodied benthics. Both the limnetic and benthic fishes have significantly higher escape fast-start velocities than their ancestral form, the anadromous threespine stickleback Gasterosteus aculeatus, suggesting that the high performance of the Paxton Lake sticklebacks is an evolutionarily derived trait. In this biomechanical study of functional morphology, we demonstrate that similar high fast-start performance can be achieved by different suites of morphological characteristics and suggest that predation might be the selective force for the high escape performance in these two fishes.

Improving Performance of a Multi-Bit Arithmetic Logic Unit

2021 ◽  
Vol 26 (1) ◽  
pp. 40-53
Author(s):  
A.N. Yakunin ◽  
◽  
Aung Myo San ◽  
Khant Win ◽  
◽  
...  
Keyword(s):  
High Speed ◽  
Operating Time ◽  
Arithmetic Logic Unit ◽  
Maximum Delay ◽  
Sequential Organization ◽  
Quartus Ii ◽  
Logic Unit

In modern microprocessors to reduce the time resources the arithmetic-logic units (ALU) with an increased organization of arithmetic carry, characterized by high speed, compared to ALU with sequential organization of the arithmetic carry, are commonly used. However, while increasing the bit number of the input operands, the operating time of ALU of ALU with the accelerated arithmetic carry increases linearly depending on the number of bits. Therefore, the development of ALU, providing higher performance than the existing known solutions, is an actual task. In this work the analysis of ALU with sequential and accelerated organization of the arithmetic carry has been performed. To increase the speed of the operation, a multi-bit ALU has been developed. The simulation of ALU circuits has been executed in Altera Quartus –II CAD environment. The comparison has been performed by the number of logical elements and the maximum delay as a result of modeling the ALU circuits for 4, 8, 16, 32, and 64 bits. A scheme for checking the results has been implemented to confirm the reliability of developed ALU. As a result, it has been found that when performing operations with the 64-bit operands, the developed ALU reduces the maximum delay by 53 % compared to ALU with sequential arithmetic carry and by 35.5 % compared to ALU with the accelerated arithmetic carry, respectively.

Nonlinear Vibration and Comfort Analysis of High-Speed Trains Moving Over Railway Bridges

Volume 2 ◽  
2004 ◽  
Author(s):  
M. H. Kargarnovin ◽  
D. Younesian ◽  
D. J. Thompson ◽  
C. J. C. Jones
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Beam Theory ◽  
Maximum Acceleration ◽  
Railway Bridges ◽  
Comfort Index ◽  
Power Spectral ◽  
High Speed Trains ◽  
Train Speed ◽  
Track Bridge

The ride comfort of high-speed trains passing over railway bridges is studied in this paper. The effects of some nonlinear parameters in a carriage-track-bridge system are investigated such as the load-stiffening characteristics of the rail-pad and the ballast, rubber elements in the primary and secondary suspensions systems. The influence of the track irregularity and train speed on two comfort indicators, namely Sperling’s comfort index and the maximum acceleration level, are also studied. Timoshenko beam theory is used for modelling the rail and bridge and two layers of parallel damped springs in conjunction with a layer of mass are used to model the rail-pads, sleepers and ballast. A randomly irregular vertical track profile is modelled, characterised by a power spectral density (PSD). The ‘roughness’ is generated for three classes of tracks. Nonlinear Hertz theory is used for modelling the wheel-rail contact.

Reliability Analysis

2020 ◽  
pp. 1-44
Author(s):  
Cherry Bhargava
Keyword(s):  
High Speed ◽  
Manufacturing Industry ◽  
Low Cost ◽  
Operating Performance ◽  
Operating Time ◽  
Electronic System ◽  
Health Condition ◽  
Operating Characteristics ◽  
Integrated Technique ◽  
Insight Into

As the integration of components are increasing from VLSI to ULSI level. This may lead to damage of electronic system because each component has its own operating characteristics and conditions. So, health prognostic techniques are used that comprise a deep insight into failure cause and effects of all the components individually as well as an integrated technique. It will raise alarm, in case health condition, of the components drift from the desired outcomes. From toy to satellite and sand to silicon, the major key constraint of designing and manufacturing industry are towards enhanced operating performance at less operating time. As the technology advances towards high-speed and low-cost gadgets, reliability becomes a challenging issue.

On the Premixed Combustion in a Direct-Injection Diesel Engine

1987 ◽  
Vol 109 (2) ◽  
pp. 187-192 ◽  
Author(s):  
A. C. Alkidas
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Engine Speed ◽  
Direct Injection ◽  
Premixed Combustion ◽  
Injection Timing ◽  
Oxides Of Nitrogen ◽  
Nitrogen Emissions ◽  
Direct Injection Diesel Engine ◽  
Diffusion Burning

The factors influencing premixed burning and the importance of premixed burning on the exhaust emissions from a small high-speed direct-injection diesel engine were investigated. The characteristics of premixed and diffusion burning were examined using a single-zone heat-release analysis. The mass of fuel burned in premixed combustion was found to be linearly related to the product of engine speed and ignition-delay time and to be essentially independent of the total amount of fuel injected. Accordingly, the premixed-burned fraction increased with increasing engine speed, with decreasing fuel-air ratio and with retarding injection timing. The hydrocarbon emissions did not correlate well with the premixed-burned fraction. In contrast, the oxides of nitrogen emissions were found to increase with decreasing premixed-burned fraction, indicating that diffusion burning, and not premixed burning, is the primary source of oxides of nitrogen emissions.

A Dislocation Dynamics Based Constitutive Model and Experimental Validations by 3D Microscale Laser Dynamic Forming of Metallic Thin Films

2010 ◽  
Author(s):  
Huang Gao ◽  
Gary J. Cheng
Keyword(s):  
Constitutive Model ◽  
Strain Rate ◽  
Cell Size ◽  
High Speed ◽  
Dislocation Dynamics ◽  
Dynamic Responses ◽  
Strength Increase ◽  
Strain Rate Effects ◽  
Discrete Dislocation ◽  
Thickness Variations

Microscale Laser Dynamic Forming (μLDF) shows great potential in fabricating the robust and high-aspect-ratio metallic microcomponents by the high speed plasma shockwave. Experiments revealed that strain rate and sample size play important roles in determining the final results of μLDF. To further understand the deformation behavior, we develop a constitutive model integrating size effects and ultrahigh strain rate effects to predict the ultimate plastic deformations. To derive this model, 3-D Discrete Dislocation Dynamics (DDD) simulations are first set up to investigate the dislocation evolutions and the dynamic responses during shockwave propagation. It is observed that there exist three dynamic stages during deformation process, and the initial strain hardening rate in Stage II increases with strain rate. The simulation also reveals that stain softening occurs only for the smaller cell size due to two competing mechanisms. In addition, the simulation predicts that the flow stress and yield strength increase with the strain rate and decrease with cell size. The modified mechanical threshold stress (MTS) model integrating these effects is implemented in Abaqus/Explicit and predicts the deformation depth and thickness variations in good agreement with the experimental results.

Development of Reduced Rolling Process for Steel Plate

2012 ◽  
Vol 706-709 ◽  
pp. 2101-2106
Author(s):  
Xiu Hua Gao ◽  
Hui Fang Lan ◽  
Lin Xiu Du ◽  
Chun Lin Qiu
Keyword(s):  
Low Cost ◽  
New Technology ◽  
Rolling Process ◽  
Steel Plates ◽  
High Rate ◽  
Iron And Steel Industry ◽  
Iron And Steel ◽  
Heavy Plate ◽  
New Type ◽  
Microstructure And Mechanical Property

The low cost Q460 and Q550 steel plates were produced in the 4200mm wide and heavy plate mill using Normal Hot Rolling and High Rate Cooling (NHR+HRC) process. The effect of both rolling processes on microstructure and mechanical property was studied. The results indicate that new type process can realize the good match between microstructure and mechanical properties. Meanwhile the new technology can short rolling time, reduce alloying addition, and improve the output of mill, it is also promote iron and steel industry developing continuously.

Optimization Design Based on DEFORM-3D Finite Element Analysis about Steel Rolling Production

2011 ◽  
Vol 480-481 ◽  
pp. 1079-1084 ◽  
Author(s):  
Jian Hua Ren ◽  
Wei Wang ◽  
Rong Liu
Keyword(s):  
Finite Element ◽  
Production Process ◽  
Optimum Design ◽  
High Speed ◽  
Optimization Design ◽  
Rolling Process ◽  
Element Analysis ◽  
Steel Rolling ◽  
Finite Element Software ◽  
Actual Production

This paper took the high-speed wire rod rolling process of φ20 bar as the research object, to be simulated numerically under the work platform of the finite element software DEFORM. The simulation results were compared with the actual operation of the production process, the rolling simulation reappeared the actual production situation, realized the visualization of the rolling process. After analysis, the defects of rolling technology were found out. Based on the research, the optimum design was gotten and then simulated which improved the actual production process and avoided the original defects. The optimum design is feasible to practical production and reduce the cost of test in practice The paper just focused on the first one of 12 rolling process as an example to show the simulating process and results.

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