Pass Designs Research Articles

When unlocking rivers results in building more infrastructure: A group mental model shares lessons from weir remediation in the United Kingdom

AbstractThe last several decades have seen a rise in efforts to remove weirs, but there is little research investigating how projects are carried out, potential areas for improvement, or sharing of lessons to facilitate reconnection of more rivers. The aim of the study presented here was to explore how people involved in weir remediation perceive project processes, factors that facilitate or hinder action implementation, and possible ways processes could be improved to reconnect more rivers. We carried out semi‐structured interviews with people (n = 11) who had been actively involved in weir remediation processes in the Severn River Catchment, United Kingdom, and used their responses to create a group mental model. The group mental model was created to support learning and communication about weir remediation projects between individuals and groups. We found broad agreement from those involved in creating the group mental model about weir remediation project processes and potential areas for improvement. One of the only points of divergence within the group mental model was associated with the impact of different weir remediation actions, particularly weir removal. Based on the group mental model, we set out three calls to action to reconnect more rivers in the UK. First, move beyond opportunistic projects and establish national goals and catchment‐scale plans for weir remediation. Second, reform fish passage legislation and legislate weir ownership. Doing so would support more effective remediation solutions by recognizing the diversity of fish species that reside in UK rivers and help mitigate risks from hazardous weirs through owner accountability. Third, build cross‐sector and public partnerships to encourage removal or improved fish pass designs. We direct the three calls to action to policy makers and anyone already engaged in or envisioning weir remediation projects in the UK. The calls also have potential implications and relevance to people in other countries in Europe and beyond.

Reduction of energy and fuel consumption in the hot-rolling steel sector

Furnace oil consumption, electric energy consumption, waste owing to mill scale, and process scrap due to cropping length are essential production indicators that must be monitored for economical production with minimal environmental impact.The study examined the effect of mill setting schedules or roll pass designs on furnace oil consumption, electricity consumption, mill scale generation and end cropping loss in a steel bar hot rolling plant. Rolling experiments were performed in a hot rolling steel plant. The results obtained from the rolling plant experiments were compared with the results obtained with the help of computer simulation.A t-test is an inferential statistic used to determine if there is a significant difference between the means of two groups. The results of plant experimentation and simulation were compared by performing t-test. The simulations results were found to be comparable to experimental results. After validation, simulation experiments were performed for the mill setting process parameters beyond the range possible in the rolling plant. Regression equations linking input process parameters with response parameters were created with the help of statistical analysis.The optimum mill setting parameters for minimum consumption of fuel oil, electrical energy, minimum generation of mill scale and end cropping loss have been attained.

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.

Impact of hydraulic forces on the passage of round goby (Neogobius melanostomus), gudgeon (Gobio gobio) and bullhead (Cottus gobio) in a vertical slot fish pass

AbstractEvery fish migrating upstream through vertical slot fish passes must swim through slots, where the resistance force of flowing water could affect the passage success. We measured the hydraulic force acting on the body of preserved benthic fish in a vertical slot at different water discharge rates (80 and 130 L/s) to compare the hydraulic burden individual fish species (round goby Neogobius melanostomus Pallas, 1814, gudgeon Gobio gobio L. and bullhead Cottus gobio L.) must overcome. The forces measured in three spatial axes were then compared to acoustic Doppler velocity measurements and the passage probability of 39–45 live fish per species. Passage probability reduction of 28.26% for round goby and 39.29% for bullhead was observed at the higher water discharge. Gudgeon showed increased numbers of passages and approaches when larger hydraulic forces were experienced at 130 L/s compared to the lower water discharge. Gudgeon experienced significantly lower hydraulic forces (mean 0.27 N ± 0.12 standard deviation) compared to round goby (mean 0.32 N ± 0.12 SD) and bullhead (0.35 N ± 0.14 SD). Potentially, the increased hydraulic forces at the higher water discharge contributed to the reduction in passages in round goby and bullhead. That gudgeon behaved differently from the other species illustrates how fish species deal differently with flowing water and the hydraulic forces experienced. Our approach provides a species‐oriented assessment of the flow field in ecologically relevant fish passes. These findings represent an important step towards the development of purposeful fish pass designs, which is essential for ecosystem‐oriented river connectivity.

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.

Optimization of roll calibrations for beam channel rolling. Part 2. Space of channel gauges

The optimization of roll pass design for rolling of channels based on the conception of two-stage optimization was realized. Roll pass design is independent functioning system and has two components of optimization: roll pass design scheme and pass schedule. Roll pass design will be considered truly optimal only if it has both an optimal scheme and an optimal pass schedule. During the first-stage optimization (search the optimal scheme of roll pass design), the most important moment is the formation of the “space of channel grooves” as the first space optimization. The above space consists of channel grooves of various types and shapes determined by known from the literature and practice roll pass designs. The “space of channel grooves” must be regularized with the use of the method of classification. As the main features of classification (groove space coordinates), the mostimp ortant geometric and technological features of the grooves were chosen: type of neck, type of actual flanges, type of false flanges, type of groove closure and quantity of rolls constituting the groove. Levels of variation for every criterion of classification have been identified and coded. Every admissible combination of variation levels specifies type and code of particular scheme of channel groove.Acknowledgements: The reported study was funded by RFBR, project number 20-38-90246.

Development of new roll pass designs for ball-rolling rolls with continuously variable parameters

This article outlines modern approaches to the creation of roll passes for helical rolling mills for the production of grinding balls. The key feature is the roll design with continually varying parameters of its elements. Such elements include: flange width varying along the length of the roll; flange height, with a nonlinear function of flange rising; pitch of the helical groove which maintains constancy of the volume of the metal being deformed. Particular attention is paid to a new conceptual pass design for ball-rolling rolls with a variable groove depth, the prospects of which are connected with uniformity of reduction and the production of balls not only with the correct geometry, but also with a more homogeneous structure. The article shows functions of a continuously varying pitch of a helical groove of rolls with a constant and variable flange width, as well as with a variable depth of the groove. A practical test was conducted on ball-rolling rolls for production of balls with a nominal diameter 120 mm with continuously varying pitch. Experience has shown positive results both in reducing loads and in increasing the dimensional accuracy.

Technical Feasibility Assessment for Roll Pass Designs in Three-High Shape-Mill Stands in Modern Mini-Mills

Construction and commissioning of a network of mini-mills of various maximum production volumes requires installation of equipment. Several plants have developed mills in which continuous-reduction stands have been replaced by three-high stands. Despite prior experience in using continuous-cast billets for production of a variety of rolled shapes in modern continuous mills, use of this approach in shape mills with three-high reduction stands requires an technical feasibility assessment of the new forming modes and pass designs used for these modes. Comparative analysis indicated that the newly developed billet forming modes and pass designs did not fully achieve the requisite technical feasibility. The stress-strain behavior in the early passes facilitates not only formation of end cracks, but also increases the likelihood of discontinuity defects in the metal over the entire free surface of the billet not in contact with the bottom or corners of the pass due to development of tensile stresses. Absence of reduction in the initial box passes during rolling of continuous-cast billets therefore will lead to rhombicity defects. Using excessively high reductions in individual passes makes clamping of the process cross section less stable, increases the likelihood of overfilling the pass, and increases the peak rolling load in certain passes Collectively this suggests that these process characteristics indicate that a better-validated approach is needed for determination of continuous-cast billet rolling schedules for three-high reduction stands.

Individual-based model of juvenile eel movement parametrized with computational fluid dynamics-derived flow fields informs improved fish pass design.

European eel populations have declined markedly in recent decades, caused in part by in-stream barriers, such as weirs and pumping stations, which disrupt the upstream migration of juvenile eels, or elvers, into rivers. Eel passes, narrow sloping channels lined with substrata that enable elvers to ascend, are one way to mitigate against these barriers. Currently, studded eel tiles are a popular substrate. This study is the first to evaluate the flow fields within studded eel tiles and to model the swimming performance of elvers using cellular automata (CA) and individual- (or agent-) based models. Velocities and flow depths predicted by a computational fluid dynamics model of studded eel tiles are first validated against published values for a single installation angle–discharge combination. The validated model is then used to compute three-dimensional flow fields for eel passes at five different installation angles and three inflow discharges. CA and individual-based models are employed to assess upstream passage efficiency for a range of elver sizes. The individual-based model approximates measured passage efficiencies better than the CA model. Passage efficiency is greatest for shallow slopes, low discharges and large elvers. Results are synthesized into an easy-to-understand graphic to help practitioners improve eel pass designs.

One size does not fit all: inter- and intraspecific variation in the swimming performance of contrasting freshwater fish.

Artificial barriers cause widespread impacts on freshwater fish. Swimming performance is often used as the key metric in assessing fishes' responses to river barriers. However, barrier mitigation is generally based on the swimming ability of salmonids and other strong swimmers because knowledge of swimming ability for most other freshwater fish is poor. Also, fish pass designs tend to adopt a 'one size fits all' approach because little is known about population or individual variability in swimming performance. Here, we assessed interspecific and intraspecific differences in the sustained swimming speed (Usus ) of five freshwater fish with contrasting body sizes, morphologies and swimming modes: topmouth gudgeon, European minnow, stone loach, bullhead and brown trout. Significant U sus variation was identified at three organizational levels: species, populations and individual. Interspecific differences in Usus were as large as 64cms-1, upstream populations of brown trout showed mean U sus 27cms-1 higher than downstream populations, and species exhibited high individual variation (e.g. cv = 62% in European minnow). Sustained swimming speed (U sus) increased significantly with body size in topmouth gudgeon, European minnow and brown trout, but not in the two benthic species, bullhead and stone loach. Aerobic scope had a significant positive effect on U sus in European minnow, stone loach and brown trout. Sustained swimming speed (U sus) decreased with relative pectoral fin length in European minnow and brown trout, whereas body fineness was the best predictor in stone loach and bullhead. Hence, swimming performance correlated with a diverse range of traits that are rarely considered when predicting fish passage. Our study highlights the dangers of using species' average swimming speeds and illustrates why a 'one size fits all' approach often fails to mitigate for barrier effects. We call for an evidence-based approach to barrier mitigation, one that recognizes natural variability at multiple hierarchical levels.

Re‐establishment of fish passage for conserving threatened migratory species of West‐Indian Himalayas

AbstractFish passes are structures (natural or manmade) bypassing barriers (e.g., dams), enabling satisfactory movement of migratory fish species. Reestablishment of fish passage, including facilitating overcoming barriers presented by impoundments or restoration of defunct structures, is attracting interest among scientists and policymakers as a mechanism to enable recovery of target fish species or fish communities. However, it is also important to note that fish passes may also act as ecological traps in some large neotropical rivers. A diversity of multispecies fish passage designs have been implemented in North and South America, Europe, and Australia, with varying efficacy for different species. However, field surveys between 2010 and 2018 supported by a review of published literature (N = 217) using Google Scholar search engine using six key terms reveal that few fish passes have been constructed in dams in the Indian Himalayan region, and their efficacy is largely unproven. Major problems associated with fish pass designs include uneven success across a range of species and largely untested effectiveness at the large scale of many major dams. The objective of this paper is to stress upon the requirement of a new approach to understand the operational drawbacks of different types of fish pass and to take an adaptive approach to both design and operation using field data to improve fish pass efficiency. These measures could contribute significantly to the conservation of threatened migratory fish in the increasingly impounded rivers of the Indian Himalayan region.

Ku‐ and K‐band high‐efficiency GaN MMIC HPA chipset for satellite communications

A GaN monolithic microwave-integrated circuit (MMIC) driver and high power amplifier (HPA) chipset solution are presented for two commonly utilised satellite communications frequency bands. The MMICs represent first pass designs utilising Qorvo's recently released 0.15 µm GaN on SiC process featuring slot via devices.

Comparison of Thermal Performances between Low Porosity Perforate Plate and Flat Plate Solar Air Collector

Flat plate solar air collector is the most common collector design, which is relatively simpler to fabricate and lower cost. In the present study, perforated plate solar collector was developed to improve the system thermal performance. A glazed perforated plate of 6mm holes diameter with square geometry was designed and installed as the absorber of the collector. The influences of solar radiation intensity and mass flow rate on the thermal performance were investigated. The perforated collector was compared with the flat plate solar collector under the same operating conditions. The highest values of thermal efficiency in this study for the perforated plate (PP) and the flat plate (FP) solar collectors were 59% and 36% respectively, at solar radiation intensity of 846 Wm-2 and mass flow rate of 0.02 kgs-1. Furthermore, PP collector gave better thermal performance compared to FP collector; and compared to previous studies, the present perforated design was compatible with the flat plate with double pass designs.

Rolling simulation system for non-symmetric groove types

An extension of a previously developed rolling simulation system is presented. Complicated groove dimensions, which have no longer symmetry on any of the coordinate axis, are successfully implemented. The thermo-mechanical numerical solution, considering ideal plastic deformation and obeying von-Mises flow rule, is based on meshless local radial basis function collocation method. During the solution procedure, 2D discrete cross sectional slice of a groove and rolled material become a computational domain at a given time, parallel to each other and aligned perpendicular to the rolling direction. Groove slice, or groove surface lines, are created with the help of imaginary groove surface points for each slice position. The implementation of roll contact at the boundaries is done by considering possible contacts of a slice and groove surface line at multiple sections with different deformation rates and boundary conditions. Coulomb model of friction is considered at the contact boundaries. The design of non-symmetric (in vertical or/and horizontal direction) type of rolling schedule is quite complicated since keeping the rolled product at the center may become problematic and unexpected deformation in one direction could ruin the desired final shape. The computational model, capable of coping with non-symmetric groove geometries provides an essential simulation tool for these type of roll pass designs. To increase the stability and the accuracy, the number of collocation nodes over the slices as well as groove surface points may be suitably increased or redistributed. The simulation results are shown in terms of temperature, displacement, strain and stress fields as well as roll forces and torques. A user friendly computer application is created for industrial use based on C# and .NET.

Minimzing the value of axial forces in the cold tube rolling mills

The aim. Subsequent development of procedure for calculation of the kinematic parameters of the process of tube deformation in the cold tube pilger roll rolling mills with purpose of decreasing the value of axial forces. Methods. The new method (procedure) for the choice of the rational relationship of values of the forced rolling radius and the roll barrel radius in the mill KPW (method of the work minimum) had been assumed as the basis of development of the procedure for calculating the kinematic parameters of the tube deformation process in the cold tube pilger roll rolling mills. The outcome. The main dependencies known for now, which are used for calculating the value of the natural rolling radius and the roll barrel radius had been considered in the present paper, as well as the main practice used for decreasing the value of axial forces in the CTR mills. A procedure had been proposed for calculating the kinematic parameters of the tube deformation process in the mills of the cold tube pilger roll rolling (the method of the work minimum). Basing on the outcomes of industrial exploitation of the given method one drew the conclusion as to effectiveness of the proposed procedure. The scientific novelty. Basing on existing dependencies, the development of procedure had been proposed for calculating the rational relationship of the forced rolling groove radius and the roll barrel radius in the cold tube rolling mills. The procedure is based on the intimate analysis of axial forces, which are determined proceeding from all the basic parameters of the process. The practical importance. The given method allows optimizing not only the maximum values of axial forces at the direct and reverse stroke of the stand, but also the intensity of forces distribution along the cone of deformation. The method (procedure) had been used while calculating a number of roll pass designs for rolling tubes of titanium alloys in the mill KPW–25.

Meta-analyses, Metrics and Motivation: Mixed Messages in the Fish Passage Debate

Over recent years, there has been increasing challenge to the accepted wisdom that the environmental impacts of river engineering can be adequately mitigated through the installation of infrastructure, such as fish passes. This has led to a debate on the value of fish passage with some arguing that increased research and development will advance solutions for a variety of structures that are suitable for multiple species and transferable to different regions. Others suggest that policies and management strategies should reflect the realization that current mitigation technology frequently fails and can itself have negative impacts. Meta-analyses of the results of studies on fish passage effectiveness have led to the challenge of conventional views by highlighting lower than expected efficiencies, wide variation between and within fish pass designs, and bias towards consideration of a limited number of commercially important species mainly from northern temperate regions. Results of meta-analyses can also be controversial, and difficulties can arise when nuances associated with individual studies are lost and when metrics used are not standardized. Intrinsic variation in fish passage efficiency between and within species due to differences in patterns of movement and motivation may not be considered, and in many situations, current metrics are not appropriate. Quantification of variation in trends in fish passage efficiency over time and with spatial scale is lacking and should be the focus of future reviews. It is time to accept that fish passage does not provide a universally effective mitigation solution, particularly when designs and strategies are transferred to other regions and species for which they were not originally designed. Admitting to cases of failure is an essential first step to advancing water resources planning and regulation based on well-informed decision-making processes. Copyright © 2016 John Wiley & Sons, Ltd.

Dual‐band single‐layer quarter ring frequency selective surface for Wi‐Fi applications

This study proposes a frequency selective surface (FSS) design to be used in Wi-Fi shielding applications as either a band reject or band pass dual-band single-layer filter. The proposed design consists of a combination of basic elements, that is, ring loops/slots, and is tuned at both 2.4 and 5.2 GHz Wi-Fi frequency bands. It has a relatively stable frequency response in the aforementioned Wi-Fi bands for incidence angles ranging from 0° to 45°. Both band reject and band pass designs are presented, along with their unit cell dimensions. Simulation and model validation through measurements demonstrate the performance of the proposed FSS design. Active variants are also proposed and briefly evaluated, in simulation environment, which should allow for applications where an on-off switching is desired at 2.4 and 5.2 GHz Wi-Fi bands.

Efficacy of a nature-like bypass channel in a Portuguese lowland river

Throughout Europe in the last decade there has been a steady shift away from more technical fish pass designs to more nature-like passes, such as nature-like bypass channels. Upstream fish passage in a nature-like bypass channel was investigated in a lowland river, the Lima River, for 117 days from March 2000 to May 2002. Fish passage was recorded using an automatic video recording system. Electrofishing samples within the bypass and below the weir were compared with species abundance found on the tape recordings. More than 7500 individuals of eight species passed through the bypass channel. Species composition was dominated by striped mullet (65.3%) and potamodromous species (34.3%), which used the bypass mainly at night. Of the environmental variables considered, bypass discharge explained most of the variation in the number of cyprinids, whereas water temperature was more important for diadromous species. Comparing species composition below the weir using passage recordings provided a useful tool to assess species efficacy of the bypass, although biological requirements should also be taken into account. This study proved the efficacy of the bypass for passage of almost all occurring species and life stages and also for providing suitable habitat for fish fauna, highlighting the use of these facilities for river restoration schemes.

Flexibility and Utilization of Roll Pass Sequences in some Swedish Wire Rod Mills

A computer program has been developed to calculate the working range for series of two-symmetrical grooves including oval, round, false round, square and diamond shapes. Eight different pass designs are compared. The geometry of rolling or entry bar height over roll radius is in the range 0.09-0.26 for squares, 0.10-0.23 for false round and 0.06-0.21 for ovals. Square-oval and round-oval have similar flexibility, but in the round-oval sequence, the flexibility can be extended by opening up the gaps and run the rounds as false rounds. In the square-oval sequence the flexibility can be improved by making the squares with larger corner radii but the reduction capability will be reduced. The false round-oval sequence has the best flexibility and the working range can be extended by making “flatter” ovals. Improvement of the roll pass design in Fagersta Stainless AB has made it possible to roll wire rod with higher flexibility and better quality.

유한요소해석을 이용한 환봉 단조공정 최적화

Three-dimensional rigid-plastic finite element analysis has been performed to optimize open die forging process to make round bar. In the round bar forging, it is difficult to optimize process parameters in the operational environments. Therefore in this study, finite element method is used to analyze the practice of open die forging, focusing on the effects of reduction, feeding pitch and rotation angle for optimal forging pass designs. The soundness of forging process has been estimated by the smoothness and roundness of the bar at various combination of feeding pitches and rotation angles. From the test result, process conditions to make round bar having precise dimensional accuracy have been proposed.