Pass Design Research Articles

Decoding burst swimming performance: a scaling perspective on time-to-fatigue.

Fatigue curves quantify fish swimming performance, providing information about the time ([Formula: see text]) fish can swim against a steady flow velocity (Uf) before fatiguing. Such curves represent a key tool for many applications in ecological engineering, especially for fish pass design and management. Despite years of research, though, our current ability to model fatigue curves still lacks theoretical foundations and relies primarily on fitting empirical data, as obtained from time-consuming and costly experiments. In the present article, we address this shortcoming by proposing a theoretical analysis that builds upon concepts of fish hydrodynamics to derive scaling laws linking statistical properties of [Formula: see text] to velocities Uf, pertaining to the so-called burst range. Theoretical arguments, in the present study, suggest that the proposed scaling laws may hold true for all fish species and sizes. A new experimental database obtained from over 800 trials and five small-sized Cypriniformes support theoretical predictions satisfactorily and calls for further experiments on more fish species and sizes to confirm their general validity.

Determination of Ungated Ogee Spillway Length so as to Pass Design Flood Safely

Determination of Ungated Ogee Spillway Length so as to Pass Design Flood Safely

Performance Evaluation of Solar Photovoltaic Thermal Air Collector Based on Energy and Exergy Analysis

This work presents a comprehensive parametric study of thermal and electrical performance of four different designs of photovoltaic/ thermal air heaters (PV/T) based on energy and exergy analysis. The results are compared to that from the conventional design of flat duct PV/T. The main goal of these designs is to enhance the heat transfer inside the air duct and consequently to increase the system's electrical power output. A computer simulation program has been developed in order to calculate the electrical and thermal PV/T collector parameters. The results indicate that an increase of 52, 52.4, and 68.25 % in the total system efficiency has been achieved from the corrugated duct, double pass design and finned duct respectively. Furthermore, at a low mass flow rates the electrical efficiency has also been improved for the three types by 9.8, 14.6 and 12.6 % respectively compared to that of flat duct design. The temperature of the PV arrays has a major effect on the exergy efficiency and removing heat from the PV module keeps the net power output at satisfactory level.

Expert Elicitation for the Resilient Design and Optimisation of Ultra-long Ore Passes for Deep Mass Mining

Extension of ore pass length has become increasingly critical for optimising energy-efficient underground mining operations. Long and ultra-long ore passes, spanning from 300 to 700 m, can significantly improve the functionality and viability of underground mass mining operations though suboptimal performance has an extremely adverse impact on production. The public domain lacks substantial information regarding the primary engineering, geological, and geotechnical risks and challenges associated with the design, implementation, operation, and maintenance of such long ore passes. Therefore, the aggregation of past experiences and the insights of experts assume paramount significance. An innovative methodology is introduced to address this evident data deficiency and to establish comprehensive guidelines for the resilient design of such lengthy ore passes — combining gap analysis with expert elicitation techniques. This equips design engineers with the necessary tools to formulate and adapt strategies for assessing the numerous challenges and uncertainties that invariably accompany their projects. Expert elicitation techniques are summarised, and a gap analysis is conducted with subject matter experts, from various countries, collating their extensive ore pass design experience, to create a comprehensive list of effective parameters and key risks that must be considered. Quantitative analysis of the survey results enabled the identification and ranking of the numerous factors affecting the design, operation, and maintenance of long and ultra-long ore passes and highlights the complex technical challenges (substantial damage from rock particle impact, increased dynamic mining stresses leading to failure, air-blasts and back blasts, dust, preferential flow, turbulent and dynamic material flow) that are uncommon in shorter ore passes. Additionally, increasing length heightens the probability of intersecting weak rock or discontinuities, leading to a higher risk of structural failure and instabilities. Faulting, folding, and large-scale structures are also critical geological factors to be considered in the design of such structures. The key geotechnical factor is also the rock type surrounding the pass. Experts highlighted the lack of clear guidelines for decision-making, resilient design, and construction so this work suggests future investigations to determine the complex interaction between the effective parameters, using approaches like the rock engineering system, discovery of cascading hazards, and optimal controls.

Cold rolling pass design and process based on controlling the distribution of material strain energy density

To address the problem of excessive grain boundaries and difficulty in eliminating defects on the inner surface of a pipe under a cold rolling pass, a method to control the distribution of material strain energy density is proposed, and a reasonable reduction in wall thickness is designed. An analysis model for inner surface defects was established using the inner wall adhesion value as the main criterion to quantitatively analyze the degree of defects on the pipe's inner surface. A systematic analysis of the rolling process of three different pass-opening shapes revealed that the opening shape dramatically affects the deformation and flow of the metal. During the rolling process, because of the unreasonable distribution of metal deformation caused by the existing pass design, the pipe is prone to high or concentrated stress, resulting in a low adhesion value for the inner wall and a greater degree of defects on the inner surface. Therefore, we propose a new opening shape and reasonably allocate the wall thickness reduction of the pipe to obtain a new pass. Numerical simulation reveals that, after rolling with the new pass, the inner wall adhesion value becomes relatively high, and the mechanics parameters have also been improved. The experimental results show that, under the new pass design, grain boundaries on the inner surface of the pipe are reduced and the smoothness is significantly improved, proving the feasibility of a cold rolling pass design based on controlling the distribution of material strain energy density.

From Material Requirements to the Rolling Schedule - Fast Material-Oriented Roll Pass Design for Long Products with the Open Source Framework PyRolL

From Material Requirements to the Rolling Schedule - Fast Material-Oriented Roll Pass Design for Long Products with the Open Source Framework PyRolL

Experimental study on the probabilities of kinked arches and kinked arch locations in ore passes under the influences of multiple factors

A smooth shaft production process is important to ensure the safe and efficient development of mineral resources. Due to the influence of ore rock and the mismatch between rock size and ore pass design, an arching phenomenon occurs frequently during actual ore pass release, stagnating production. Therefore, an ore pass release simulator with a freely variable ore pass angle and height is designed and used to conduct a four-factor, five-level orthogonal ore pass release experiment. An analysis is performed to determine the influence of four factors—ore particle size, ore moisture, ore pass inclination and slip height—on the probability of ore pass arching; from there, an ore pass arching probability equation is constructed and the characteristics of the ore pass arching location are clarified, effectively predicting the probability of ore pass arching and providing an effective basis for handling arching events within an applicable range. This analysis effectively predicts the probability of ore pass arch within the applicable range, and provides an effective basis for handling ore pass arch events.

A Desirability-Based Solution Search Method for Sequential Optimization of the Hot Rolling Process

Abstract Although it is an old technique, research on the hot rolling process maintains its importance because of its widespread usage in steel production and its requirement for a vast amount of resources, especially energy. The roll pass design of the hot rolling process considerably affects many operational parameters such as energy requirement, roll wear, working forces, and torques. Furthermore, due to the sequential nature of the rolling process, a design of any number of passes is closely interrelated with all other passes in the process. This complexity makes it challenging to find optimal design solutions that strike a balance between conflicting goals and constraints. In this article, a new optimized solution search strategy based on a desirability function is offered to address the sequential characteristics of the roll pass design. A novel optimization method utilizing response surfaces and the proposed solution search strategy is presented to reduce the shaping energy of the overall process while minimizing turning moments and radial forces on rolls during the rough rolling process. The proposed method provides integrated optimization of the process by ensuring information flow between the passes and can also be applied to other sequential processes with some modifications. The developed method and solution search strategy are illustrated and validated through a case study. The findings of the case study are compared to three distinct pass designs used in industrial power plants. The results show significant energy savings, lower turning moments, and reduced radial forces compared to the reference designs.

Numerical assessment of interstand tensions in continuous hot rolling processes of flat and long products

The paper deals with the calculation of interstand tensions in continuous rolling mills.In the rolling mill industry, continuous measurement and data collection of roll forces, roll torques, temperatures and roll velocities is possible. However, the important process parameter of interstand tensions is not directly measurable and no direct calculation of the interstand tensions is possible. The interstand tensions couple the effects of subsequent roll gaps and should therefore by known for a holistic recalculation of the process. It is straightforward to calculate the effects of the tensions on roll forces, torques and the stock velocity. The inverse problem of calculating the acting interstand tensions including their effects from the process parameters is of greater interest but also of a higher complexity, because the interactions between all the stands in the rolling mill must be regarded. The present paper aims at filling this research gap by presenting a mathematical model to solve the inverse problem by a linearization of the tensions influences in the rolling mill. The present model does not require measured roll forces or torques to find the interstand tensions, only the rotational velocities of the rolls and the rolling parameters (material, temperature, pass schedule or pass design) must be known. Tension-dependent spread is considered by an empirical sub-model. Results are shown for the tension distributions in strip and rod mills. The results indicate that the present friction conditions and the entry size of the rolled stock have a high impact on the tension distributions.

Literature Review of Low Pass Filters Based on CMOS for Biomedical Applications

Abstract: A survey of low pass filters with good linearity, low weight, and low power consumption has been done in this study .we examine the numerous low pass filter types ,their uses and design factors in this survey. we start by looking at low pass filters fundamental concepts and characteristics of their frequency response. in this study ,many low pass filter types and associated technologies are discussed. Low pass filter with low noise ,low power requirements, and low weight have been shown to be an implementing RKTG pairs in low pass filter circuits by varying the aspect ration of MOSFETs manufactured at 45nm,90nm,and 180nm technologies. this survey is valuable resource for engineers and scientists study in signal processing and communication systems since it offers a through review of low pass filters and their uses

Analysis of the Microstructure Development of Nb-Microalloyed Steel during Rolling on a Heavy-Section Mill.

It is not realistic to optimize the roll pass design of profile rolling mills, which typically roll hundreds of profiles, using physical modelling or operational rolling. The use of reliable models of microstructure evolution is preferable here. Based on the mathematical equations describing the microstructure evolution during hot rolling, a modified microstructure evolution model was presented that better accounts for the influence of strain-induced precipitation (SIP) on the kinetics of static recrystallization. The time required for half of the structure to soften, t0.5, by static recrystallization was calculated separately for both situations in which strain-induced precipitation occurred or did not occur. On this basis, the resulting model was more sensitive to the description of grain coarsening in the high-rolling-temperature region, which is a consequence of the rapid progress of static recrystallization and the larger interpass times during rolling on cross-country and continuous mills. The modified model was verified using a plain strain compression test (PSCT) simulation of rolling a 100-mm-diameter round bar performed on the Hydrawedge II hot deformation simulator (HDS-20). Four variants of simulations were performed, differing in the rolling temperature in the last four passes. For comparison with the outputs of the modified model, an analysis of the austenite grain size after rolling was performed using optical metallography. For indirect comparison with the model outputs, the SIP initiation time was determined based on the NbX precipitate size distribution obtained by TEM. Using the PSCT and the outputs from the modified microstructure evolution model, it was found that during conventional rolling, strain-induced precipitation occurs after the last pass and thus does not affect the austenite grain size. By lowering the rolling temperature, it was possible to reduce the grain size by up to 56 μm, while increasing the mean flow stress by a maximum of 74%. The resulting grain size for all four modes was consistent with the operating results.

IMPROVEMENT OF THE METHOD FOR CALCULATING DEFORMATION PARAMETERS IN THE ROLL PASS DESIGN FOR THE WIRE MILL

Currently, analytical methods, including system analysis and computer simulating, are widely used in the development and construction of rational roll pass design. However, the known methods and solutions are not exhaustive, which solve the problem completely. The methodology for calculating the parameters of rolling deformation during the calibration of rolls for rolling wire rod in system of the gauges "round-oval-round" on graded modern continuous mills has been developed, taking into account the balance of the forces in the deformation zone and the longitudinal stability of the process. It provides coordination of geometric, kinematic and force parameters in the deformation zones of the rolling mill itself and the wire block.
 The calculation is carried out against the direction of rolling, in terms by the corresponding strip, taking into account temperature conditions and rolling in the field of minus tolerances the dimensions of the metal. Longitudinal rolling stability in every stand is determined based on the calculation the average resulting internal forces of plastically deformable metal. Numerically solving the boundary value problem for the Karman equation with known rolling parameters and changing the entering angle, the corresponding angle of the neutral section is found, the value of which is equal to the found kinematic one.
 The results of the test calculations are quite close to the real data of rolling the round bar and a wire rod with a diameter of 8 mm on a mill 400/200 of PJSC "KAMET-STEEL". At the same time, the broadening of the metal is determined analytically in accordance with the physical conditions of the balance forces and constancy of the seconds’ volumes of the metal in the zones of deformation. The shape of the ovals obtained by the provided method is more convex. The system influence of metal friction conditions in the rolls on the longitudinal stability of rolling and the stability of the process was established.

Development and perspectives of rolling of rib stiffened plate

Thin-wide aluminium rib stiffened plate structure reduces the weight and provides high stiffness, which makes it in high demand in transportation vehicles, marine, and structural applications for energy saving and CO2 emission reduction. In this study, the applicability of rolling in manufacturing an integral rib stiffened plate is reviewed through analysis of different rolling processes. The effect of rolling parameters and rib geometry on the formation and quality of ribs are analysed. The analysis provides an important basis to advance the understanding of metal flow, viscoplastic deformation and roll shape design during rolling, significantly helping the design of an innovative rolling process for rib stiffened plate. In addition, geometry and rolling parameters, plate curvature, and roll pass design (RPD), that highly affect the rolling process design are discussed. This paper presents the limitations and improvements of specific shape rolling processes and preliminarily concludes that rolling could be a potential method to produce high quality thin-wide panels with high stiffeners.

The concept of optimal bar roll pass design. Report 4. Optimization of roll pass design scheme

Roll pass design of shape rolling rolls is considered from the standpoint of system analysis within “UrFU concept of optimal roll pass design” created in the Chair “Metal Forming” of the Ural Federal University. Roll pass design as a technological system can be changed in two methods: 1) changing the structure of the system which corresponds to a change in the groove shape; 2) changing the control of the system, which corresponds to changing reduction through the pass in the grooves, that is, by changing the reduction mode. Roll pass design that compose of the definite grooves and realize the definite reduction mode, which assures of optimal properties of preassigned objective function depending on the specified parameters, is considered optimal. General conception of two-stage optimization of roll pass design: consistent conduct of optimization of roll pass design scheme (first stage of optimization) and mode of reduction (second stage of optimization), was considered in previous reports. Procedures of formation of optimization space for first stage – space of virtual schemes of roll pass design generated by the special generator and set of all possible types of grooves that can be used at this particular stage of rolling, were also described. To calculate the objective function of the optimality criterion of the roll pass design scheme, the authors introduced the concept of “space of grooves efficiency”. Formation of this space is carried out using a formalized procedure for expert evaluation of the degree of influence of various permissible forms of grooves used in roll pass design on the diverse technological, economic and other characteristics of a particular rolling mill. The objective function is calculated as variance of integral performance indicators of the grooves included in the roll pass design relative to the hypothetical “ideal” groove with the best values of the selected performance indicators. The roll pass design scheme corresponding to the minimum value of the objective function is considered the best.

Multipass hollow fiber membrane modules for membrane distillation

Membrane distillation (MD) is an interesting process for desalination; however high thermal energy consumption remains one of the main obstacles in its widespread adoption. The current study presents multipass hollow fiber membrane modules to improve thermal efficiency of MD process. Fundamentally three module designs are considered: conventional one shell and one tube (fiber) pass (A), 1 shell and multiple tube passes (B/C) and equal but multiple shell and tube passes (D). The performance of the proposed designs is analyzed as a function of length of each pass, number of passes and operating conditions by using Aspen Plus simulator. The results demonstrate that the traditional design A yields the highest flux — up to 92 % higher than the multipass design D. On the other hand, the multipass design D is the most energy efficiency and shows up to 35 % less thermal energy consumption than the conventional single pass design of the same length. Single shell and multiple tube pass designs (B/C) show higher flux than D; however, their specific thermal energy consumption remains the highest among all the designs investigated. The pressure drop in multipass modules was marginally (1.5 %) higher than the conventional single pass modules.

Concept of Optimal Bar Roll Pass Design. Report 4. Optimization of Roll Pass Design Scheme

This study considers roll pass design from the standpoint of system-level analysis within the UrFU concept of optimal roll pass design developed at the Department of Metal Forming of the Ural Federal University. Roll pass design as a process system is changed by two methods, that is, either by changing the structure of the system, which corresponds to changes in the groove shape, or by changing the control of the system, which corresponds to changing reductions by passes in one and the same grooves, that is, by changing reduction mode. The roll pass design that is considered optimal contains such grooves and uses such reduction mode, at which the extreme properties of preset target functions are ensured depending on the indicated parameters. In previous reports, the general concept of the two-stage optimization of roll pass design is considered. This concept implies a consistent optimization of the roll pass design scheme (optimization stage one) and reduction mode (optimization stage two). In addition, procedures of shaping the optimization space for stage one are considered. This space includes virtual roll pass design schemes and is shaped by the special generator of these schemes and the set of all possible types of grooves that can be used at this particular stage of rolling. To calculate the target function of the optimality criterion of the roll pass design scheme, the groove efficiency space concept is introduced. This space is shaped by the formalized expert assessment of the degree of influence of various permissible forms of grooves used in roll pass design on the diverse technological, economic and other characteristics of a particular rolling mill. The target function is calculated as variance of integral performance indicators of the grooves included in the roll pass design relative to the hypothetical ideal groove with the best values of selected performance indicators. The roll pass design scheme corresponding to the minimal target function is considered the best.

Computer Simulation of a New Two-Threaded Roll Pass Design for Rolling 100 mm Grinding Balls Made of Alloyed Steels

Computer Simulation of a New Two-Threaded Roll Pass Design for Rolling 100 mm Grinding Balls Made of Alloyed Steels

The Influence of Changes in Roll Pass Design on the State of Residual Stresses in Railway Rails – Summary

The Influence of Changes in Roll Pass Design on the State of Residual Stresses in Railway Rails – Summary

Data-Driven Roll Pass Design of Wire Rod Mills

The classical approach for roll pass design of a wire rod mill employs an iterative technique incorporating spread calculation and rectangular equivalent pass methods. This method comes to its limits in terms of computational efficiency and numerical stability when a complete pass design for a wire rod mill with lots of different final dimensions and materials must be designed. To improve the pass design technique, a fast data-driven method for pass design based on synthetic data generated by the classical pass design model was created. The results are compared to the original training data, as well as newly generated test data. It is shown that the artificial neural network (ANN) is able to predict appropriate oval groove geometries with good precision.

Improvment of a Double-Helical Roll Pass Design for Rolling 100-mm Grinding Balls

Improvment of a Double-Helical Roll Pass Design for Rolling 100-mm Grinding Balls