Rib Width Research Articles

Supplementation with 25-hydroxicolecalciferol increases the nutritional efficiency and carcass growth of grazing Nellore young bulls

We aimed to evaluate the effect of 25-OH Vit D3 (Hy-D, DSM, Brazil) supplementation on the performance, body measures, and carcass characteristics of growing and finishing grazing Nellore young bulls. Two experiments were conducted. In Experiment 1, 150 animals (body weight (BW) of 350 ± 23kg) were separated into 6 treatment groups: protein supplement (PS); protein supplement with monensin (PS+Mon); protein supplement with 25-OH Vit D3 (PS+Vit D3); protein supplement with monensin and 25-OH Vit D3 (PS+Mon+Vit D3); protein-energetic supplement (PE); protein-energetic supplement with 25-OH Vit D3 (PE+Vit D3). In Experiment 2, 240 animals with an initial BW of 390 ± 16kg were separated into the same protein-energetic supplement treatment groups used in Experiment 1 with or without 25-OH Vit D3 (two treatments). Animals in the different treatments of Experiment 1 had similar ADG and final BW values (P > 0.05), except for those that received monensin in PS, which showed lower ADG (P < 0.05). The addition of monensin to the PS inhibited increases in the body measures (P < 0.05) except for the height at withers (P > 0.05). Animals that received PE+Vit D3 showed greater increases in rib width (P < 0.05). In Experiment 2, animals that received 25-OH Vit D3 were 8.0kg heavier than the animals that did not receive this supplement (P < 0.05). The results show that supplementation with 25-OH Vit D3 is a promising and effective method of improving carcass weight and yield in finishing beef cattle during grazing.

Improving water retention and mass transport for low-humidity proton exchange membrane fuel cells via a porous-channel interdigitated flow field

The power density in low-humidity proton exchange membrane fuel cells (PEMFCs) is restricted by low membrane hydration level induced ohmic loss and low efficient oxygen supply induced concentration loss. Herein, a porous-channel interdigitated flow field (PIFF) is proposed to boost the cell performance by simultaneously enhancing water retention and mass transport. A three-dimensional multi-physical PEMFC model is applied to investigate the cell performance, water transport and species distribution. It is demonstrated that PIFF is effective in improving cell performance, due to the improved dissolved water content and under-rib oxygen supply. In the same water vapor capacity, the distribution of reactants relative humidity (RHa and RHc) affects cell performance, where the peak power density of PEMFC at RHa = RHc = 0.5 is lower than that at RHa = 0.8 and RHc = 0.2. The peak power density can be maximumly increased by increasing rib width at the ratio of rib width increment to channel width increment (ΔWrib/ΔWch) equaling to −0.5, but can be hardly increased at ΔWrib/ΔWch = 2. The mode with anode gases inlet direction being totally opposite to the cathode can maximumly enhance the cell performance at low reactants relative humidity. This work provides a high-performance flow field design for low-humidity PEMFCs.

Machine learning prediction of interfacial bond strength of FRP bars with different surface characteristics to concrete

Fiber-reinforced polymer (FRP) bars have been implemented in civil infrastructures as internal reinforcement. The bond strength of FRP bars to concrete depends on the surface characteristics considerably. This study used machine learning (ML) techniques to explore the influence of bar surface types on the bond properties quantitatively. A database including 158 FRP bars-concrete pull-out testing results was compiled. The geometric factors, including rib spacing (wc), rib width (wf) and rib height (rh), were proposed to quantify the surface configurations of FRP bars. Twelve ML models were trained to predict the interfacial bond strength. The ML models demonstrated higher accuracy in predicting the bond strength compared to eight existing equations from the literature. Among these models, CatBoost exhibited the highest accuracy, with an RMSE 58.3 % lower than the most accurate existing equation. CatBoost was utilized in parametric research on the influencing factors, and demonstrated that wf had the highest weight contribution to interfacial bond strength. Additionally, this study effectively combines ML models with physical meaning-driven analysis methods, resulting in a practical and interpretable equation for calculating FRP bars-concrete interfacial bond strength.

Effect of rib width on the thermo-electro-mechanical behavior of solid oxide fuel cells

In this study, a three-dimensional multi-physics coupled model is employed to investigate the effects of the rib width of the cathode-side interconnect on the flow characteristics, electrochemical performance, temperature distribution and stress distribution of solid oxide fuel cells (SOFCs) under cross-flow conditions based on a fixed gas channel-electrode interface area. The results show that as the rib width is reduced, there is a marked improvement in the uniformity of gas distribution and gas flow velocity within the channels, leading to an increase in the output power density of the SOFC stack, a reduction in the temperature gradient of the cell and a reduction in the thermal stress carried by the cell. However, if the ribs are of insufficient width, the pressure drop within the channels will be significantly increased, reducing the static pressure head of the gas and leading to a decrease in the gas flow velocity within the electrodes. This, in turn, will result in an increase in concentration polarization and higher manufacturing costs. The simulation results facilitate a more detailed comprehension of the internal reaction processes of SOFCs, thereby offering valuable guidance for the structural optimization of interconnects.

Investigation of roll forming process and quality control factors for metal bipolar plates

Metal bipolar plates (BPPs) are crucial components of proton exchange membrane fuel cells (PEMFCs), with the quality of their formation affects the power generation efficiency and lifespan of the fuel cells. The predominant manufacturing method, stamping, often results in localized excessive stretching of metal BPPs, thereby limiting the depth of the flow channels. Roll forming, dominated by bending deformation, is a forming process that ensures uniform thinning and greater depth of BPPs. The multi-directional flow channel roll forming model for BPPs is constructed in this paper for the first time, the characteristics of the roll forming process is investigated. Effects of process parameters on the forming results are discussed. The investigation indicates that during the roll forming process, the channel ports and corners are critical areas where defects are most likely to occur. The average filling ratio of the longitudinal flow channels is 5.6% higher than that of the transverse flow channels. The plastic strain in the longitudinal flow channels is about 36% higher than in the transverse ones, which making the form is more difficult to form, but the thickness is more uniform. Increasing the diameter of the rollers can enhance the filling ratio and flatness, but it will exacerbate thinning at the corners of the flow channels. When the ratio of the flow channel width to the rib width is close to 1, the filling ratio of the BPP is higher, with less thinning, resulting in a better forming result. As the depth of the flow channel increases, resulting in a thinner BPP, when depth-to-width ratio exceeding 0.6 is more likely to lead to failure. Increasing the speed of roll forming can lead to a greater thinning of the BPP and may even cause it to crack. The thinner the sheet metal is, the higher the filling ratio of the BPP and the more uniform its thickness. Those results can provide technical references for the structural design and forming process optimization of BPPs.

Robust design optimization of five‐phase SynRM for fault‐tolerant operation based on Taguchi method

AbstractSynchronous reluctance motor has recently attracted the attention of researchers due to their characteristics such as higher efficiency compared to induction motors, lower cost in contrast to permanent magnet motors, robust rotor structure and limited rotor inertia. Also, research on five‐phase motors, which have more reliability and torque density than three‐phase motors, is of a great importance. In this essay, the optimization of the robust design of a five‐phase reluctance synchronous motor has been done through the design of experiments using the sequential Taguchi method based on fuzzy logic. To ensure that the performance of the motor is not sensitive to changes and uncertainties, the air gap manufacturing tolerances, the width of the rotor's tangential rib and the rotor's pitch control angle are considered as noise factors. In addition, to improve the motor's fault tolerance capacity, the main performance characteristics of the motor under single‐phase fault operation, such as average torque and ripple torque are considered as optimization targets, along with the main performance characteristics of the motor under normal operation. By comparing the optimization results of the proposed method with the conventional Taguchi optimization method, the effectiveness and superiority of the proposed method have been confirmed.

Multi-Objective Optimization Strategy for Commercial Vehicle Permanent Magnet Water Pump Motor Based on Improved Sparrow Algorithm

In order to achieve multi-objective optimization for a permanent magnet water pump motor in heavy commercial vehicles, we propose a strategy based on response-surface methodology and the improved sparrow algorithm (CGE-SSA). Firstly, the output capacity of the pump during actual operation was tested with an experimental bench to determine the design parameters of the motor, and then its modeling was completed using Ansys Maxwell 2022r2 software. Secondly, the response-surface model was established by taking the parameters of permanent magnet width, rib width, and slot width as optimization parameters and the output torque (Ta), torque ripple (Tr), and back electromotive force (EMF) amplitude as optimization objectives. Meanwhile, three methods—namely, circular sinusoidal chaotic mapping, improved golden sinusoidal strategy, and adaptive weight coefficients—were used to improve the convergence speed and accuracy of the sparrow search algorithm (SSA). Finally, the multi-objective optimization of the permanent magnet synchronous motor was completed using the improved sparrow algorithm. A comparative analysis of the motor’s output before and after optimization showed that the torque pulsation and reverse electromotive force of the motor were significantly improved after optimization.

Optimizing thermal performance in internal passage cooling with extended rib: Applying response surface method with artificial neural networks

Efficient cooling technology is crucial for high-temperature gas turbines which are significant applications in thermal processes particularly in industries such as power generation aerospace and marine propulsion. Enhancing cooling efficiency in these systems not only improves energy utilization but also plays a critical role in reducing fuel consumption increasing operational reliability and minimizing environmental impacts. This research focuses on optimizing the thermal performance of internal passage cooling channels with extended ribs using a combination of the response surface method and artificial neural networks. By varying the extended rib length and rib width the study aims to enhance heat transfer and minimize flow loss leading to improvements in overall system efficiency. Latin Hypercube Sampling is employed to strategically select variables and automated numerical simulations are conducted to perform a thorough parametric analysis. A steady-state k-ω shear stress transport turbulence model is applied in the simulations and the numerical results are validated against experimental data ensuring accuracy. The combined response surface method–artificial neural network approach integrated with TensorFlow-based modeling allows for the prediction of heat transfer and friction factor ultimately generating a comprehensive response surface to identify the optimal design point. Applying the optimized design leads to a 23.99 % improvement in the thermal performance factor compared to the reference case. The findings of this study highlight a significant enhancement in the thermal performance of the cooling channel structure particularly in high heat flux environments. This research provides valuable insights into the design of more efficient thermal management systems for gas turbines and has broader implications for other high-temperature thermal processes. The proposed optimization methodology offers a reliable approach for improving cooling technologies contributing to the development of the next generation of energy-efficient high-performance gas turbines and other industrial applications where effective thermal management is essential.

Advances in Fuel Cell Performance Using Simulation Analysis in Toshiba Energy Systems & Solutions Corporation

The influence of channel and rib width of bi-polar plates on gas diffusion performance was investigated by simulation and experimental measurement. Simulation results showed that a ch./rib ratio of about 2 is a compromise between diffusivity and resistance, and that higher performance can be expected. The advanced cell with bi-polar plates with this flow channel geometry was fabricated and its performance was evaluated. IV characteristics of advanced cell exceeded simulation results, indicating that the effect of improved GDL/MPL tortuosity on diffusion performance was greater than expected.

Performance Characteristics of a Free-Breathing Polymer Electrolyte Fuel Cell with Various Channel Shapes

This study utilized a small free-breathing fuel cell, with an active area of 4 cm2 (2 cm x 2cm), and channel cathodes with various channel shapes, to experimentally investigate the effect of channel structure on cell performance, to numerically analyze the natural convection air flow in channels, and to compare with the results of performance characterisitics. The results indicated that, compared with a conventional cathode separator with four straight channels (with a width of 3 mm, a depth of 3 mm, and a rib width of 2 mm), cell performance was improved by eliminating some of the channel ribs and increasing the opening ratio, up to a point. A separator with 2 mm square ribs rotated by 45° further improved cell performance. However, when the opening ratio exceeded 72% with a straight center rib of 2 mm width, cell performance leveled off. The analysis results revealed that separators with modified channels promoted natural convection.

Advances in Fuel Cell Performance Using Simulation Analysis in Toshiba Energy Systems & Solutions Corporation

The influence of channel and rib width of bi-polar plates on gas diffusion performance was investigated by simulation and experimental measurement. Simulation results showed that a ch./rib ratio of about 2 is a compromise between diffusivity and resistance, and that higher performance can be expected. The advanced cell with bi-polar plates with this flow channel geometry was fabricated and its performance was evaluated. IV characteristics of advanced cell exceeded simulation results, indicating that the effect of improved GDL/MPL tortuosity on diffusion performance was greater than expected.

An experimental investigation on the performance of direct methanol fuel cell using new anode and cathode flow field designs

This is a comprehensive study of the DMFC through the introduction of new channel designs. A traditional serpentine design with a rib and channel width of 0.8mm on an area of 50mm×50mm is designated as design-1 and used as the reference channel design. Three other new designs are fabricated and tested in comparison with design-1. A 4-outlet, 1-inlet, 4-zone serpentine with 0.8mm of rib and channel width, is designated as design-2. A 4-outlet, 1-inlet, 4-zone serpentine with a converging channel width is designated as design-3. A 4-outlet, 1-inlet, 4-zone zigzag serpentine with a converging channel width is designated as design-4. The study was done in three stages. The first stage investigates the effect of anode channel designs by fixing the cathode design to design-1 and varying the anode designs from design-1 to design-4. The second stage investigates the effect of cathode designs by fixing the anode design to design-1 and varying the cathode designs from design −1 to −4. The third stage investigates the effect of using the same designs at both the anode and cathode sides. All the stages were tested using three anode flowrates (2,5, and 8mL/min) and three methanol concentrations (1, 2, and 3mol/L). Higher concentrations perform better than lower concentrations while lower flowrates perform better than higher flowrates. The percentage improvement by the new designs in comparison to the reference design is: 142%, 94%, and 136% for the first stage; 74%, 125%, and 40% for the second stage; and 16%, -33% and -45% for the third stage, and the order being design −2, −3 and −4 respectively. Design −3 and −4 underperform in the third stage due to the availability of direct paths that boost methanol crossover when using the same design of anode and cathode. The new designs evacuate the CO2 bubbles and byproduct water faster and more efficiently than the reference design.

Cathode fine-scale flow channel optimization enhancing the performance of proton exchange membrane fuel cells

High performance and long durability have been the continuous pursuit of proton exchange membrane fuel cells (PEMFCs). Performance and durability are related to the PEMFC distributional uniformity of internal state, which are deeply influenced by the flow channel structures and operating conditions. Therefore, this study proposes a fine-scale flow channel (FSFC) with gradually decreasing flow channel widths (wch) based on parallel flow field. Following, fixing wch at 0.3 mm, the effects of different rib width (wrib), cathode humidity (RHc), stoichiometric ratio (ξc) and coolant mass flow rate (mcool) are studied. Simulation results indicate that FSFC can significantly enhance the various properties of fuel cells, especially the performance and uniformity. Reducing the wrib can enhance the performance and reduce the pressure drop. The appropriate RH and ξc can improve the performance and uniformity while avoiding flooding and purging effects. Similarly, mcool should be kept in the appropriate range to avoid unnecessary pump power loss. This study aims to develop the flow fields in a more fined direction, offering solutions that strike a balance between durability and power density for PEMFC optimization.

Thermal Performance and Building Energy Simulation of Precast Insulation Walls in Two Climate Zones

Traditional concrete buildings exhibit low energy consumption and high heat loss, which results in a larger environmental problem. Precast insulation walls are proposed for strengthening thermal insulation efficiency and mitigating heat loss. Numerous studies have investigated the thermal performance of insulation walls over the past decades. However, gaps remain in practical engineering applications. This study aims to bridge these gaps by providing practical design recommendations based on experimental research. Nine different types of precast insulation walls were tested to examine the thermal performance, and the parameters of the insulation material, insulation form, insulation layer thickness, and concrete rib width were investigated. Then, numerical models of these walls were developed for simulating the thermal performance of the tested specimens. Finally, a six-story student apartment model using designed walls was developed to assess energy consumption in two distinct climate zones: the hot summer and cold winter zone of Changsha City, and the cold zone of Harbin City. The results indicate that the precast insulation wall with external insulation form shows better thermal performance than the sandwich insulation form. It is recommended to use precast insulation walls with 50 mm extruded polystyrene (XPS) external thermal insulation form in Changsha City and 80 mm XPS external thermal insulation form in Harbin City. Furthermore, buildings using precast insulation walls can significantly reduce energy consumption by 49.25% in Changsha and 49.38% in Harbin compared to traditional concrete wall buildings. Based on these findings, suitable design suggestions for this precast concrete wall panel building composed of insulation walls are given.

Modeling for plastic instability in multi-directional rotary forging of thin-walled components with three ribs

Multi-directional rotary forging has the great potential to form thin-walled components with three ribs because of its incremental deformation characteristic and smaller forging load. However, for the components with thin-walled sterna and thick ribs, the plastic instability is easier to occur at the bottom of thick ribs in multi-directional rotary forging, resulting in the waste of components. Therefore, the aim of this paper is to establish the model for predicting plastic instability in multi-directional rotary forging of thin-walled components with three ribs. Firstly, the models for calculating actual and critical radial stresses on both sides of rib are established by analyzing complicated stress states caused by time-varying thinning deformation of sterna and thickening deformation of rib. It is found that the critical radial stress is mainly determined by ratio of deformation energy and external force work, while the actual radial stress is mainly determined by dissipated power and metal flow velocity. By combining actual and critical radial stresses, a unified model for simultaneously predicting plastic instability of ribs at different positions is proposed. Then, the influence laws of different technical parameters on critical conditions of plastic instability are revealed. It is found that the plastic instability is mainly determined by initial thickness of workpiece and width of rib, i.e., the critical deformation amount increases with increasing initial thickness of workpiece or decreasing width of rib, and vice versa. Finally, the experiments are conducted to verify that the proposed model for predicting plastic instability in multi-directional rotary forging of thin-walled components with three ribs is reliable. This paper provides a guideline to establish the model for predicting plastic instability under complicated stress states and metal flow modes.

Experimental studies on bond behaviour of steel rebar with different rib patterns in concrete

The bond between concrete and steel rebar is one of the most crucial parameters in the construction of reinforced concrete structures. The load-bearing capacity and serviceability of these structures depend heavily on bond strength. The rib pattern of the rebar plays a significant role in enhancing bond behaviour. The impact of different rebar patterns on bond studies in the concrete mix is found to be limited. In the study, six concrete mixes were prepared and tested. Three of these mixes incorporated fly ash in varied amounts to partially replace cement, while the other three mixes had no fly ash. Three different rib patterns of steel bars were embedded into these six grades of concrete. The pull-out tests were used to assess the bond strengths of various combinations in accordance with RILEM recommendations. The findings show that the ribs in rebars significantly increase mechanical interlocking whereas the presence of fly ash improves chemical adhesion in bond behaviour. Particularly, pattern 2 rebar (transverse rib thickness, 0.797 mm; transverse rib width, 2.06 mm; rib spacing (inner to inner), 6.428 mm; longitudinal rib thickness, 1.04 mm; longitudinal rib width, 2.312 mm; rib inclination angle, 66.39o; nominal diameter, 16 mm; length of transverse rib, 25 mm) exhibited notably superior bond strength, reaching a maximum of 17.21 MPa in M30 grade concrete in which 95 kg/m³ of fly ash was used as a replacement for cement.

Multi objective optimization using artificial neural network to maximize the power output of PEMFCs

ABSTRACT Designing a PEM fuel cell model is exceedingly challenging because of its multivariate in nature. Optimization is required to achieve highest operating condition. Neural Network Model is one of the possible methods to solve complex problems. The polarisation curve of a PEMFC (Proton Exchange Membrane Fuel Cell) is investigated in this paper in relation to the effects of seven parameters, including temperature, relative humidity in the cathode, relative humidity in the anode, anode stoichiometry, cathode stoichiometry, partial pressure of H2, and partial pressure of O2, using an ANN (artificial neural network) model. Where model geometric parameters i.e. Channel width, Channel depth, Channel length, Rib width, Cell width, GDL thickness, CL thickness, Membrane thickness of PEMFC was constant. Initially single Objective Function (Output Power) is predicted. The research presented here makes predictions about a PEMFC stack's electrical performance under multiple operating conditions. Mathematical model was further verified using laboratory data. Co-efficient of Determination (R2), Mean Square Error (MSE), and Mean Absolute Error (MAE) was determined using the fuel cell stack voltage model and stack power model. The model results show the possibility of using ANN in the implementation of such models to predict the PEMFC system's steady-state behaviour.

Impact of the flow-field distribution channel cross-section geometry on PEM fuel cell performance: Stamped vs. milled channel

Polymer electrolyte membrane fuel cells (PEM FCs) represent an essential part of the emerging hydrogen economy. Metallic bipolar plates (BPs) allow high speed and capacity production using established industrial technologies, like mechanical stamping. Stamping, however, leads to different cross-sectional shapes of flow-field (FF) channels as compared to milled or compression-moulded bipolar plates. The impact of these changes on the resulting fuel cell performance is not yet fully understood. This study employs an experimentally validated three-dimensional, isothermal, steady-state, continuum-mechanics based mathematical model to gain a deeper insight into this issue and to identify optimal stamped BP channel cross-sectional shapes for parallel and serpentine FF. The uniformity of the local distribution of the physico-chemical quantities and the resulting load curves are analysed. The results obtained confirm that stamped BPs with channels of the trapezoidal cross-section are a viable alternative to the traditional milled or moulded BPs with channels of the rectangular cross-section. The observed differences in performance of FC with stamped and milled channels can be mitigated by optimization of the channel cross-section geometry parameters. As an optimal rib width 0.4 mm and an optimal channel ground width 1 mm for milled and 0.2 mm for stamped BPs are suggested.

Improve the Flexural Behavior of One-Way Ribbed Slab by Using CFRP Sheet

One of the most important research projects in the recent years is strengthening structures. The significance of these studies was to modify the ability of buildings to withstand high loads without utilizing materials that hurt the environment. Six one-way ribbed slabs were experimentally tested in the present study to determine the effect of carbon fiber reinforcement polymer sheets on the structure. One of the specimens, used as a reference, was unstrengthen. Two specimens were strengthened with carbon sheets on 50% and 100% of the rib width. To prevent sheet debonding, two others used 50-mm-wide U-shaped strips. A complete rib wrap served as the final method of strengthening. All the specimens underwent concentrated load testing to investigate the ultimate capacity, deflection, stiffness, and ductility. According to the findings, all specimen’s deflection decreased in a ratio ranging from 4% in whole rib wrap to 46%. Also, the stiffness increased in all specimens, and the width of the carbon sheet insignificantly affected the stiffness, while the way of strengthening did. In the end, strengthening with 50% width has no discernible effect on the ultimate load (3%), whereas strengthening with 100% width raised by 41%, while adding U-shaped stripes increased the ultimate load capacity by 74% and completely wrapping the ribs increased by 132%.

Bond performance between ribbed BFRP bar and seawater sea-sand concrete: Influences of rib geometry

To solve the corrosion problems of steel bars in reinforced seawater sea-sand concrete (SSC) structures, fibre reinforced polymer (FRP) bars are promising alternatives. The bond between FRP bars and SSC determines the capacity and serviceability limit states of structures composed by them. The rib geometry of FRP bars is one of the most important factors influencing their bond performances with concrete. However, it has not received sufficient attentions on existing studies and standards. Therefore, this study investigated the bond performance between SSC and ribbed basalt FRP bars with different rib geometry through pull-out tests on 36 specimens. It is found that the bond strength declined with the increase of rib width and dent width, while the increase of rib height improved the bond strength. The ultimate and residual slip were strongly correlated with the rib spacing. Finally, a bond strength model that can well predict the experimental results was proposed.