Stack Resistance Research Articles

Communication—Prediction of Area Specific Resistance of Solid Oxide Cell Stacks from Electrochemical Impedance Spectra

A support vector regression model was trained to predict the area specific resistance of solid oxide cell stacks from electrochemical impedance spectroscopy measurements. In particular, the minimum necessary frequency range required for accurate predictions was investigated. Therefore, 711 pairs of DC polarization and electrochemical impedance spectroscopy measurements, conducted at the same stage of stack degradation and under similar measurement conditions, were evaluated. Prediction accuracies of less than 8% mean absolute percentage error and coefficients of determination greater than 93% were achieved. The 101–102 Hz range is sufficient for accurate predictions, allowing an efficient and non-destructive etimation of DC polarization measurements.

Comparing the Effect of Isoinertial Flywheel Training and Traditional Resistance Training on Maximal Strength and Muscle Power in Healthy People: A Systematic Review and Meta-Analysis.

This systematic review and meta-analysis aimed to analyze whether isoinertial flywheel training (FWT) is superior to traditional resistance training (TRT) in enhancing maximal strength and muscle power in healthy individuals. Electronic searches were conducted in the Web of Science, PubMed, Cochrane Library, SPORTDiscus, and Scopus databases up to 21 April 2024. Outcomes were analyzed as continuous variables using either a random or fixed effects model to calculate the standardized mean difference (SMD) and 95% confidence intervals (CI). A total of sixteen articles, involving 341 subjects, met the inclusion criteria and were included in the statistical analyses. The pooled results indicate no statistically significant differences between FWT and TRT in developing maximal strength in healthy individuals (SMD = 0.24, 95% CI [-0.26, 0.74], p = 0.35). Additionally, the pooled outcomes showed a small-sized effect in muscle power with FWT (SMD = 0.47, 95% CI [0.10, 0.84]), which was significantly higher than that with TRT (p = 0.01) in healthy individuals. Subgroup analysis revealed that when the total number of FWT sessions is between 12 and 18 (1-3 times per week), it significantly improves muscle power (SMD = 0.61, 95% CI [0.12, 1.09]). Significant effects favoring FWT for muscle power were observed in both well-trained (SMD = 0.58, 95% CI [0.04, 1.13]) and untrained individuals (SMD = 1.40, 95% CI [0.23, 2.57]). In terms of exercise, performing flywheel training with squat and lunge exercises significantly enhances muscle power (SMD = 0.43; 95% CI: 0.02-0.84, and p = 0.04). Interestingly, FWT was superior to weight stack resistance training (SMD = 0.61, 95% CI [0.21, 1.00]) in enhancing muscle power, while no significant differences were found compared to barbell free weights training (SMD = 0.36, 95% CI [-0.22, 0.94]). This meta-analysis confirms the superiority of FWT compared to TRT in promoting muscle power in both healthy untrained and well-trained individuals. Squats and lunges for FWT are more suitable for improving lower limb explosive power. It is recommended that coaches and trainers implement FWT for six weeks, 2-3 times per week, with at least a 48 h interval between each session. Although FWT is not superior to free weights training, it is advisable to include FWT in sport periodization to diversify the training stimuli for healthy individuals.

Sequential breakdown of the Cf-9 leaf mould resistance locus in tomato by Fulvia fulva.

Leaf mould, caused by Fulvia fulva, is a devastating disease of tomato plants. In many commercial tomato cultivars, resistance to this disease is governed by the Cf-9 locus, which encodes five paralogous receptor-like proteins. Two of these proteins confer resistance: Cf-9C recognises the previously identified F. fulva effector Avr9 and provides resistance during all plant growth stages, while Cf-9B recognises the yet-unidentified F. fulva effector Avr9B and provides mature plant resistance only. In recent years, F. fulva strains have emerged that can overcome the Cf-9 locus, with Cf-9C circumvented through Avr9 deletion. To understand how Cf-9B is circumvented, we set out to identify Avr9B. Comparative genomics, transient expression assays and gene complementation experiments were used to identify Avr9B, while gene sequencing was used to assess Avr9B allelic variation across a world-wide strain collection. A strict correlation between Avr9 deletion and resistance-breaking mutations in Avr9B was observed in strains recently collected from Cf-9 cultivars, whereas Avr9 deletion but no mutations in Avr9B were observed in older strains. This research showcases how F. fulva has evolved to sequentially break down the Cf-9 locus and stresses the urgent need for commercial tomato cultivars that carry novel, stacked resistance genes active against this pathogen.

Hamstrings Hypertrophy Is Specific to the Training Exercise: Nordic Hamstring versus Lengthened State Eccentric Training.

The hamstring muscles play a crucial role in sprint running but are also highly susceptible to strain injuries, particularly within the biceps femoris long head (BFlh). This study compared the adaptations in muscle size and strength of the knee flexors, as well as BFlh muscle and aponeurosis size, after two eccentrically focused knee flexion training regimes: Nordic hamstring training (NHT) vs lengthened state eccentric training (LSET, isoinertial weight stack resistance in an accentuated hip-flexed position) vs habitual activity (no training controls: CON). Forty-two healthy young males completed 34 sessions of NHT or LSET over 12 wk or served as CON ( n = 14/group). Magnetic resonance imaging-measured muscle volume of seven individual knee flexors and BFlh aponeurosis area, and maximum knee flexion torque during eccentric, concentric, and isometric contractions were assessed pre- and post-training. LSET induced greater increases in hamstrings (+18% vs +11%) and BFlh (+19% vs +5%) muscle volumes and BFlh aponeurosis area (+9% vs +3%) than NHT (all P ≤ 0.001), with no changes after CON. There were distinctly different patterns of hypertrophy between the two training regimes, largely due to the functional role of the muscles; LSET was more effective for increasing the size of knee flexors that also extend the hip (2.2-fold vs NHT), whereas NHT increased the size of knee flexors that do not extend the hip (1.9-fold vs LSET; both P ≤ 0.001). Changes in maximum eccentric torque differed only between LSET and CON (+17% vs +4%; P = 0.009), with NHT (+11%) inbetween. These results suggest that LSET is superior to NHT in inducing overall hamstrings and BFlh hypertrophy, potentially contributing to better sprint performance improvements and protection against hamstring strain injuries than NHT.

Comparative transcriptome analysis of canola carrying a single vs stacked resistance genes against clubroot.

Pyramiding resistance genes may expand the efficacy and scope of a canola variety against clubroot (Plasmodiophora brassicae), a serious threat to canola production in western Canada. However, the mechanism(s) of multigenic resistance, especially the potential interaction among clubroot resistance (CR) genes, are not well understood. In this study, transcriptome was compared over three canola (Brassica napus L.) inbred/hybrid lines carrying a single CR gene in chromosome A03 (CRaM, Line 16) or A08 (Crr1rutb, Line 20), and both genes (CRaM+Crr1rutb, Line 15) inoculated with a field population (L-G2) of P. brassicae pathotype X, a new variant found in western Canada recently. The line16 was susceptible, while lines 15 and 20 were partially resistant. Functional annotation identified differential expression of genes (DEGs) involved in biosynthetic processes responsive to stress and regulation of cellular process; The Venn diagram showed that the partially resistant lines 15 and 20 shared 1,896 differentially expressed genes relative to the susceptible line 16, and many of these DEGs are involved in defense responses, activation of innate immunity, hormone biosynthesis and programmed cell death. The transcription of genes involved in Pathogen-Associated Molecular Pattern (PAMP)-Triggered and Effector-Triggered Immunity (PTI and ETI) was particularly up-regulated, and the transcription level was higher in line 15 (CRaM + Crr1rutb) than in line 20 (Crr1rutb only) for most of the DEGs. These results indicated that the partial resistance to the pathotype X was likely conferred by the CR gene Crr1rutb for both lines 15 and 20 that functioned via the activation of both PTI and ETI signaling pathways. Additionally, these two CR genes might have synergistic effects against the pathotype X, based on the higher transcription levels of defense-related DEGs expressed by inoculated line 15, highlighting the benefit of gene stacking for improved canola resistance as opposed to a single CR gene alone.

Thermal and Electrical Resistance of HTS Tapes Stacks in Radial Direction

Thermal and Electrical Resistance of HTS Tapes Stacks in Radial Direction

Direct conversion of monopotassium L-aspartate by electrodialysis metathesis: Stack resistance, co-ion transport, and concentration polarization

The conventional method of synthesizing high-value amino salt from amino acid ammonium involves several steps including acidification, precipitation, and separation. This process not only consumes acids and bases but also generates a substantial amount of wastewater. In this study, monoammonium L-aspartate was directly converted to monopotassium L-aspartate (Asp-K) using electrodialysis metathesis (EDM). To achieve this, K2SO4 was chosen as the optimum potassium salt to supply K+ due to its relatively lower co-transport rate with SO42− ions and lower stack resistance. Additionally, the membrane type was optimized as CIS/AIS membranes due to their low stack resistance, high ion permeability for the transport of Asp− ions, and low concentration polarization. The process resulted in high-purity Asp-K (99.8 %) and low energy consumption (0.14 kWh/kg Asp-K). These results indicate that the EDM process is a promising method for converting amino salts with high purity.

Unveiling the role of membrane properties in water and salt transport and performance of a concentration gradient battery

The concentration gradient battery (CGB) has numerous advantages, such as zero pollution emissions and the use of non-toxic electrolytes, making it a promising candidate for integrating renewable energy into the power grid. The use of high-performance membranes is a necessary condition for the application of CGB, but the specific membrane characteristics that contribute to desired CGB performance have not been clearly defined. In this study, five commercial membranes were employed to investigate the relationship among membrane permeation of water and salt, stack resistance, and battery performance. The results highlighted the pivotal roles of membrane permeability and resistivity in determining the CGB performance. Among the membrane tested, Selemion, notable for its low permeability and resistivity, was found to effectively break the trade-off between current and voltage efficiency. This superior performance is attributed to its distinctive membrane properties of low water volume fraction and high fixed charge density. This study further suggested that strategies aimed at controlling membrane swelling and increasing fixed charge density hold great promise in enhancing the membrane performance in CGB application. This research provides insights into membrane selection and customization for CGB and serves as a reference for other membrane processes focused on energy conversion.

Improved Power Production in Reverse Electrodialysis Stacks with Ion‐Permselective Woven Net Spacers

In traditional reverse electrodialysis (RED) stacks, the output power is severely lost due to the shadow effect caused by the nonpermselective spacers. To inhibit the spacer shadow effect, a design on ion‐permselective woven net spacer is proposed. By combining the linear sweep voltammetry and electrochemical impedance spectroscopy methods, the effectiveness of permselective woven net spacer is validated together with the shadow effect and concentration polarization measured quantitatively. Additionally, their influence on stack resistance and power production is investigated under various factors. When contrasted to nonpermselective spacers, the use of permselective woven net spacers reduces the spacer shadow effect by 90% whereas also exacerbating the concentration polarization. This results in a higher power density due to a dramatic reduction in resistance. However, compared with permselective spacers, the permselective woven net spacers increase the power density due to its weaker concentration polarization. The factors including the solution concentration, temperature, and spacer thickness have a considerable influence on the power production of stack. Especially, increasing the concentration of concentrated solution alone is most beneficial to improving the output power while the impact of spacer thickness is the weakest.

Analysis of Pushing Forces During the Water Polo Eggbeater: Reliability and Validity of a Novel Approach.

Water polo players benefit from greater odds of success when maintaining their tactical position against their opponents. This study evaluated the reliability and validity of a water-based resistance test to replicate this skill.Thirty-three water polo players participated in this study (19 males and 14 females, 14 from senior and 19 from junior national teams). Data were collected during two regular training sessions, separated by one week, using a load cell to instrument a weight stack resistance setup on the pool deck. Performance parameters such as mean force, maximum force, mean peak force and total impulse were defined with custom Python scripts. Test-retest reliability was assessed using intra-class correlations (ICC3,1). Group comparisons were explored between male and female players. Level of significance was set at p < 0.05. The reliability findings were high to very high for the mean force, maximum force, mean peak force, inter-stroke range, and total impulse (ICC 0.85-0.93, p < 0.01). Group comparisons showed significantly greater values in male players for these variables (p < 0.01, ES = 1.05-9.36) with large to very large effect sizes. However, there was no significant difference in endurance measured between sexes (p = 0.88, ES = 0.04). This study presents a methodology with satisfactory metrological qualities for field applications using simple and affordable equipment. The testing apparatus presented in this study can readily be replicated in a variety of training environments by practitioners working with water polo teams. Coaches can use this approach to evaluate individual player progress or to compare performance across a group of water polo players.

Mismatch and mix: Making use of electrokinetic aspects of spacers for intensified electrodialysis

Electrodialysis (ED) processes are limited in terms of practical current densities due to the emergence of concentration boundary layers. A great deal of research has focused on methods to promote mixing of these boundary layers, particularly through developing new spacers. Spacers are crucial to the performance of electrodialysis stacks, forming the flow channels between membranes and leading to hydrodynamic mixing that reduces mass transport limitations. Conventional analysis of spacers in ED has focused on characterizing the hydrodynamic mixing resulting from spacer geometry and assessing how this impacts the overall stack resistance. In this work, we explore the electrokinetic aspect of spacer performance: the electric-field bending induced by polymeric spacers and resulting electro-osmotic mixing. We carried out an experimental study to characterize the ED performance of a lab-scale stack using spacers with different surface charge densities, using polyelectrolyte adsorption on the spacers. Our results show that substantial increases in the current density or reductions in power consumption can be achieved when making use of this enhanced mixing due to electro-osmosis. We also explain this enhancement through the use of a simplified theoretical model to highlight the potential of utilizing electrokinetic mixing from spacers in electrodialysis.

Effects of physical and operating parameters on the performance of a concentration gradient battery for saltwater-based energy storage

Concentration gradient batteries (CGBs) use electrodialysis and reverse electrodialysis to charge and discharge, respectively. An important factor hindering CGB efficiency is osmosis through ion exchange membranes (IEMs); however, adding an osmotic ballast to the dilute compartment reduces osmosis and improves CGB efficiency. Despite the importance of osmosis in CGB performance, there has been no evaluation of the effects of CGB parameters on performance with and without an osmotic ballast. Accordingly, our goal was to evaluate the effects of selected CGB parameters on various CGB performance metrics to inform future optimization of CGB designs. Results showed ballast addition improved current and round-trip energy efficiency and stabilized CGB performance across multi-cycle operation. However, ballast addition caused lower average (net) power densities due to its impact on IEM stack resistance and solution viscosity. Increasing the flowrate and decreasing the spacer thickness led to decreases in average net power densities. Importantly, the effect of IEM properties on CGB performance varied with ballast addition: low water permeability IEMs had greater and lower round-trip energy efficiencies without and with ballast, respectively, compared to low resistance IEMs. This work informs CGB parameter selection, demonstrates tradeoffs associated with osmotic ballast addition, and shows multi-cycle CGB operation is feasible.

High -yield Fabrication of Thin Glass Interposers

Thin glass substrates with through vias (TGV) have excellent properties for a new generation of interposers. Glass has a large bulk resistance and low loss at high frequency (RF, mmWave). Physically, it is moisture insensitive, highly dimensionally stable, and has a thermal expansion coefficient that can be tailored to match silicon. The surface of as-received glass has roughness below 1 nm, like silicon wafers, and thus supports fine line/space patterning and advanced processes like damascene. A key focus of our current work involves metallizing thin glass interposers with TGVs, including both copper electroplating of TGVs and patterning of redistribution layers. We demonstrate void-free fill for vias ranging from in aspect ratio from 2:1 to 8:1, in a bottoms-up process like that used for through silicon vias. The vias are hermetic by helium leak detection, even after annealing in some cases to 450C. Since thin (≤ 200 micron) free-standing glass substrates are difficult to handle in current fabs, we discuss an advanced temporary bond approach using silicon or glass handles which enables high-yield processing. The bond is robust to temperatures exceeding 400 °C, and creates handle/glass stacks with total thickness variation (TTV) similar to that of a silicon wafer. The end result is a bonded pair that can be processed like a silicon wafer, with a simple mechanical debond to yield the processed thin glass. We discuss the bond and debond processes, showing the ability to control the bond strength. Data on the bonded glass stack resistance to various processing steps will also be shown.

Untapped Sources of Dual Resistance to Hessian Fly and Greenbug in Synthetic Hexaploid Wheats.

The Hessian fly (Hf) and greenbugs (Gb) are major pests of wheat, causing severe economic losses globally. Deploying resistant wheat is the most effective strategy for managing these destructive insects. However, the resistance is not effective against all Hf or Gb biotypes and can impose selection pressure on insects, resulting in the development of virulent biotypes. These challenges must be met through the discovery of new and novel sources of resistance to these pests. Synthetic Hexaploid Wheat (SHW)-developed cultivars are a rich source of resistance against a diverse array of pathogens and pests. In this study, 80 SHW lines were evaluated for their resistance to Hf and Gb under controlled environmental conditions. Of these, a total of 36 SHW lines showed resistance independently to Hf biotype L and Gb biotype E, while 27 lines showed combined resistance to both Hf and Gb. Further, a subset of 10 SHW lines showed resistance to additional Hf biotypes, Great Plains and vH13. The identification of SHW lines resistant to multiple insects and biotypes offers an invaluable resource to breeders who are looking to stack resistance traits to develop elite cultivars as a strategy to alleviate economic impacts upon global wheat production.

Self-Supporting Microporous Layer for Polymer Electrolyte Fuel Cells

The gas diffusion layer (GDL) used in a PEFC is thicker than the electrode catalyst layer and electrolyte membrane. Thinning down the GDL can reduce gas diffusion resistance and volumetric power density of PEFC stacks. In this study, MPL/GDL is prepared by printing microporous layers (MPLs) on carbon meshes of several tens of micrometers thick as substrates for thin-layer GDLs. Through various current-voltage and overvoltage measurements and microstructural analysis of the cells using these thin-layer MPL/GDLs, cell performance has been improved, equivalent to that of the state of the MPL/GDL.

Investigation of the effect of impurity concentration in the simulated industrial saline water on the scaling phenomenon on ion exchange membranes

One of the most critical problems to be solved in membrane separation processes is the fouling of membranes. Fouling causes a reduction in current efficiency in processes using ion-exchange membranes. In this study, the mechanism of fouling on the anion exchange membrane, cation exchange membrane, and bipolar membranes caused by impurities such as CaCl2, MgCl2, Na2CO3, and NaHCO3 in the electrodialysis process of the feed solution containing NH4Cl and NaCl as the main components were investigated. The effects of initial impurity concentration on bipolar membrane electrodialysis stack resistance, demineralization, ion flux, acid and base conversion, and concentration of produced acid and base were investigated. SEM-EDX, XRD, FTIR, and TGA analyses were used for membrane characterization. Chemical cleaning was done to remove impurities in the membrane and spacer structure. The effects of chemical cleaning on cell performance were determined by comparing the process performances before and after cleaning. Experimental results showed that ions such as Ca2+ and Mg2+ in the feed solution cause precipitate on the cation exchange membrane and spacers in the base compartment. The results revealed that these precipitates do not cause structural damage to the membranes but affect their performance.

Stacking host resistance genes to control Globodera pallida populations with different virulence

Potato Cyst Nematodes (PCN) are a globally important and economically extremely damaging potato pest. Chemical control has limited impact and cannot clear a field of PCN, but genetic resistance in potatoes is an effective and important part of natural management of PCN. There are two closely related species of PCN; Globodera rostochiensis against which the H1 resistance gene from S. tuberosum ssp. andigena (CPC 1673) has proven effective in Europe for several decades, and G. pallida for which potato varieties with resistance are also commercially available. However, G. pallida resistant genotypes are mainly limited to processing varieties and most varieties grown are still susceptible to the species. The limited number of suitable varieties with resistance against G. pallida has led to its spread throughout the UK and now infestations in Scottish seed land are threatening the future of potato seed production. Novel potato genotypes with resistance against G. pallida sometimes combine PCN resistances from more than one parental source. Multiplication of a panel of G. pallida populations which differ in virulence against host species were compared on recently developed breeding lines with single or stacked resistance genes. Potato genotypes with multiple resistance genes show reduced multiplication in G. pallida pathotypes that were able to overcome a single resistance gene.

ITRAQ based proteomic analysis of rice lines having single or stacked blast resistance genes: Pi54/Pi54rh during incompatible interaction with Magnaporthe oryzae.

The online version contains supplementary material available at 10.1007/s12298-023-01327-3.

Progress of the Evaluation and Analysis Methods for Durability of SOFC Stacks

Recent progress in the development of R&D for the evaluation and analytical methods of SOFC stack durability is reported under the NEDO Japanese national project. The goal of this project is the following two points: (1) to develop the advanced evaluation and analytical methods for the cell stacks which show a lifetime over 15 years (130 kh) with high efficiency of over 65% LHV, and (2) to develop the evaluation and analytical methods for dynamic operation mode such as rapid start-stop and load cycling. Three practical stacks (one flat tube and two types of planar) were supplied by the stack developers and tested over 10,000 hours with high fuel utilization (Uf~85%). It was found that the same evaluation methods can be applied to the stack resistance component determination between normal Uf (=75%) and high Uf (85%) conditions. Relatively stable performances were reported for these stacks and degradation factors were considered taking into account the degradation mechanisms at cells and stacks. Under high Uf conditions, some specific degradation mechanisms are now analyzed in the cells. For rapid starts of stacks, evaluation protocols are considered taking into account the mechanical stress arising from the thermal distribution in the cells. Simulation methods are considered for the evaluation of performance after 15 years of operation in the stacks.

Stacking Multiple Genes Improves Resistance to Chilo suppressalis, Magnaporthe oryzae, and Nilaparvata lugens in Transgenic Rice.

The ability of various pests and diseases to adapt to a single plant resistance gene over time leads to loss of resistance in transgenic rice. Therefore, introduction of different pest and disease resistance genes is critical for successful cultivation of transgenic rice strains with broad-spectrum resistance to multiple pathogens. Here, we produced resistance rice lines with multiple, stacked resistance genes by stacking breeding and comprehensively evaluated their resistance to Chilo suppressalis (striped rice stemborer), Magnaporthe oryzae (rice blast), and Nilaparvata lugens (brown planthopper) in a pesticide-free environment. CRY1C and CRY2A are exogenous genes from Bacillus thuringiensis. Pib, Pikm, and Bph29 are natural genes in rice. CH121TJH was introduced into CRY 1C, Pib, Pikm, and Bph29. CH891TJH and R205XTJH were introduced into CRY 2A, Pib, Pikm, and Bph29. Compared with those observed in their recurrent parents, CH121TJH significantly increased the mortality of borers. The other two lines CH891TJH and R205XTJH are the same result. Three lines introduction of Pib and Pikm significantly reduced the area of rice blast lesions, and introduction of Bph29 significantly reduced seedling mortality from N. lugens. Introduction of the exogenous genes had relatively few effects on agronomic and yield traits of the original parents. These findings suggest that stacking of rice resistance genes through molecular marker-assisted backcross breeding can confer broad spectrum and multiple resistance in differently genetic backgrounds.