Loss Of Capacity Research Articles

ABOUT THE PROCESS OF ACCUMULATION OF SEDIMENTS IN THE RESERVOIR

The accumulation of sediment and the associated loss of useful reservoir capacity is a serious global problem. The problems of quantitative assessment of sediment deposits and forecasting the form of their location in the reservoir are relevant. The first of these problems has been solved quite well, but the second problem remains practically open.

Prognostic value of left atrial strain in patients with moderate to severe mitral stenosis

Abstract Background Mitral stenosis causes an inflow restriction during diastole and is characterized by an increase in left atrial (LA) pressure with reduced cardiac output. Pressure overload of the LA can lead to atrial fibrosis and remodeling, resulting in a loss of LA reservoir and compliance capacity that can lead to backward load on the pulmonary circulation. To date, there are limited studies evaluating the impact of LA strain on prognosis of mitral stenosis patients. Purpose The aim of this study was to assess the prognostic value of LA strain in patients with moderate to severe mitral stenosis using two-dimensional (2D) strain imaging. Methods This was a single-center retrospective study, 237 patients with moderate or severe mitral stenosis were enrolled from January 2010 to December 2022. Baseline clinical and echocardiographic parameters were collected, LA strain measurements with reference time point at end diastole for reservoir strain (LASr), conduit strain (LAScd) and contraction strain (LASct) were analyzed using TOMTEC software. The endpoint was a composite outcome of all-cause mortality, heart failure hospitalization and valve intervention (percutaneous transvenous mitral commissurotomy and surgical intervention). All the LA parameters were analyzed separately to avoid collinearity. Results A total of 237 patients were included in the study. The patients had a mean age was 66.56 ± 13.61 years-old and were predominantly female (67.9%) with median follow up duration is 4.54 years (IQR 1.44 – 6.44). Mean left ventricular ejection fraction (LVEF) was 56.86 ± 10.51%, mean left atrium volume index (LAVI) was 73.94 ± 55.46 ml/m2, mean for LASr, LAScd and LASct were 11.81 ± 8.89%, -6.19 ± 4.50%, and -5.58 ± 6.05% respectively. LASr with a cut-off < 15.8% was independently associated with the composite outcome of all-cause mortality, heart failure hospitalization and valve intervention on multivariable Cox regression analysis (HR 2.51, 95% CI 1.54 - 4.10, p < 0.001). LAScd, LASct and LA volume index did not demonstrate any significant association with the endpoint. Conclusion LASr was independently associated with all-cause mortality, heart failure hospitalization and valve intervention in patients with moderate to severe mitral stenosis.

Effect of incremental exercise training interventions in a Cardiac Rehabilitation Program following myocardial infarction

Abstract Background Exercise-based cardiac rehabilitation is recommended after myocardial infarction (MI) to improve prognosis, quality of life and control of cardiovascular risk factors. However, the specific impact of different exercise training interventions remains incompletely understood. Purpose To study the health outcomes of three incremental exercise training interventions during a Cardiac Rehabilitation Program (CRP) following MI. Methods We implemented a post-MI Phase 2 CRP in 2022. After initial exercise testing, a 3-month, individualized aerobic and strength ambulatory training program was provided by Cardiologists and Physical Medicine and Rehabilitation physicians (Group 1, n=58). Additionally, a subset of patients received one session of supervised teaching of aerobic and strength training by physiotherapists (Group 2, n=19), and another subset received 8-20 sessions of in-hospital supervised training (Group 3, n=13). Exercise testing was repeated at the end of Phase 2 and peak oxygen consumption (peak VO2) was measured. We analysed quality of life (SF-36), depression (PHQ2), anxiety (GAD2), adherence to Mediterranean diet (PREDIMED) and pharmacological treatment (Morisky-Green), and weekly physical activity (IPAQ). Health outcomes were compared at the beginning and after Phase 2 CRP. Results The cohort comprised 90 patients who completed Phase 2 CRP (mean age 61.2±10.8 years, 84.4% male and 47.8% smokers). Reductions in systolic blood pressure (-10.3±13.8mmHg), LDL cholesterol (-60.7±35.4mg/dL), weight (-2.8±6.6kg, -3±7.8%) and body mass index (-1±2.2) were attained (p<0.05). Smoking abstinence was accomplished in 88.4% of smokers and most patients achieved an LDL<55mg/dL (81.1%). Improvements in quality of life (SF-36 +10.4±19.4 points, p<0.001) and anxiety and depression symptoms (PHQ2 -0.5±1.6 points and GAD2 -0.6±1.6 points, p<0.01) were noted. An increase in peak VO2 (+5.12±5.44ml/kg/min, +23.5±27.4% from baseline, p<0.001) and predicted functional capacity (+13.4±23.8%, p<0.001) was achieved. Patients increased their reported weekly physical activity by 2520.3±2935.4 METS/week (+132% from baseline, p<0.001) and most of them were adherent to Mediterranean diet (91.1%) and pharmacological treatment (95.6%). Patients achieved similar health outcomes regardless of their exercise training group, except for patients in Group 3, who experienced a more pronounced improvement in peak VO2 (+8.1±6.4ml/kg/min, +37.8±34.7% from baseline; p<0.05) and a trend towards higher increase in predicted functional capacity (+21.7±19.2%, p<0.25) and greater weight loss (-5.5±9.4kg, -5.9±9.6%; p<0.2). Conclusions Supervised in-hospital training during a Phase 2 CRP provides superior physical fitness improvements and more pronounced weight loss in MI patients. However, a Phase 2 CRP based on ambulatory training provides similar benefits regarding other health outcomes, such as control of cardiovascular risk factors and quality of life amelioration.Exercise training interventions in a CRP

An Organic Small Molecule Electrode with Intermolecular Intercalation and Synergistic Effects for High‐Rate Alkali Metal‐Ion Batteries

AbstractDesignable molecular structures, unique ion‐coordination charge storage mechanisms, and resource sustainability enable organic electrode materials to become potential candidates for alkali metal‐ion batteries (AMIBs). Herein, integrating the excellent π–π stacking ability of Hexaazatriphenylene units and strong electron‐withdrawing properties of cyano (C≡N) groups into one moleuce, a π‐conjugated organic compound 1,4,5,8,9,11‐Hexaazatriphenylenehexacarbonitrile (HAT‐CN) is synthesized and systematically investigated as electrodes in Li/Na/K‐ion batteries. Explored by mechanism characterizations and density functional theory calculations, HAT‐CN can provide nine redox‐active sites for Na/K‐ions to intercalate/de‐intercalate, among which six Na/K‐ions are distributed evenly to both sides of conjugated skeletons through intermolecular intercalation and three Na/K‐ions are stored with the synergistic effect of C≡N groups. Employing HAT‐CN as electrodes, AMIBs are found to exhibit high reversible capacities, excellent rate capabilities, and stable cycle performances. After 100 cycles at the current density of 100 mA g−1, Na‐ion batteries present 415.6 mAh g−1 with a capacity fading rate of 1.2% per cycle. Meanwhile, K‐ion batteries maintain 345 mAh g−1 with a coulombic efficiency ≈100%. Li‐ion batteries display superlithiation performances with ultra‐high reversible capacity. This work emphasizes the necessity of comprehensively studying the electrochemical performance of organic electrodes in different secondary battery systems and is conducive to maximizing electrode functionality.

Review on polymer electrolytes for lithium‐sulfurized polyacrylonitrile batteries

AbstractLithium‐sulfur (Li‐S) batteries are deemed as the next generation of energy storage devices due to high theoretical specific capacity (1675 mAh g−1) and energy density (2600 Wh kg−1). However, the commercial application has always been constrained by lithium polysulfide (LiPSs) shuttling effects and still has a long way to go. Sulfurized polyacrylonitrile (SPAN) is a promising alternative candidate to replace traditional sulfur cathode and is conducive to eliminating LiPSs by realizing “solid‐solid” direct conversion in conventional carbonate electrolytes. However, an over 25% irreversible capacity loss is exhibited inevitably in the first discharge process, the inherent structure of SPAN and the related reaction mechanism remain unclear. In this review, the structure characteristics and electrochemical behaviors of SPAN are summarized for better interpreting current knowledge and favoring the design of high performance materials. In the past few decades, many problems in traditional Li‐S batteries have been solved by improving electrolytes. Polymer electrolytes (PEs) have been widely used due to structural designability, multi‐functionality, exceptional chemical stability, and excellent processability. Surprisingly, the relevant researches on PEs compatible with SPAN remains limited currently. Therefore, the recent modification strategies of gel polymer electrolytes and solid polymer electrolytes in Li‐SPAN batteries are introduced in terms of Li+ transfer and interface engineering, the design principles are concluded, the specific challenges encountered by polymer‐based electrolytes are summarized and the instructive directions for future research on PEs are demonstrated, facilitating the commercialization of Li‐SPAN batteries.

Structural stability and enhanced electrochemical performance of Co-free Li-rich layered Mn-based Li1.2Mn0.6Ni0.2O2 cathodes via F doping at the O site of lithium-ion batteries

Li-rich Mn-based Co-free layered oxides (LLOs) are promising cathode materials for lithium-ion batteries (LIBs). However, they exhibit capacity loss and low initial Coulombic efficiency. Herein, an F-doped Li1.2Mn0.6Ni0.2O1.9F0.10 material has been prepared by the high-temperature solid-state method, with numerous oxygen vacancies on the surface to accelerate Li + transport. The electrochemical performance of Li1.2Mn0.6Ni0.2O1.9F0.10 considerably improved after the treatment. A high-capacity retention of 86.9 % after 100 charge/discharge cycles at 1C was achieved for Li1.2Mn0.6Ni0.2O1.9F0.10. Results revealed that F doping replaces part of O2−, forming more force between the TM-F bonds (compared to the TM-O bond), which inhibits the cation mixing phenomenon. The layered structure stability of the material is improved after F doping, and the migration energy barrier of Li+ is reduced, which promotes the migration of Li+, thereby improving the electrochemical performance of Li1.2Mn0.6Ni0.2O2.

Performance of instrumental activities of daily living in patients with haemophilic arthropathy. A cross-sectional cohort study.

The development of haemophilic arthropathy causes joint damage that leads to functional impairment that limits the performance of activities in patients with haemophilia. The aim was to identify the best predictive model for performing instrumental activities of daily living in adult patients with haemophilia arthropathy. Cross-sectional cohort study. 102 patients were recruited. The dependent variable was the performance of instrumental activities of daily living (Lawton and Brody scale). The dependence on the performance of activities of daily living was the dependent endpoint (Barthel scale). The secondary variables were joint damage (Hemophilia Joint Health Score), pain intensity, and clinical, anthropometric, and sociodemographic variables. The degree of dependence, joint damage, pain intensity, and marital status (Cp=5.60) were the variables that best explain the variability in the performance of instrumental activities of daily living (R2 adj=0.51). Loss of predictive capacity is acceptable with good mean internal (R2 mean=0.40) and external (R2-r2=0.09) validation. According to the predictive pattern obtained, patients with haemophilia, who were married, without joint pain or damage, and independent in their day-to-day lives, had a score of 7.91 points (95% CI: 7.42; 8.39) in the performance of instrumental activities of daily living. The predictive model for the functional capacity of instrumental activities of daily living in haemophilia patients encompasses factors such as level of autonomy, joint impairment, pain severity, and marital status. Notably, despite the presence of joint damage, individuals with haemophilia exhibit a significant level of independence in carrying out both basic daily tasks and instrumental activities of daily living. Id NCT04715100.

Super Low Profile 5G mmWave Highly Isolated MIMO Antenna with 360∘ Pattern Diversity for Smart City IoT and Vehicular Communication

This study introduces a planar folded super low profile 5G mmWave monopole antenna for small IoT devices with superior efficiency and gain. Low-loss Rogers RT-5880 substrate material has been utilized to achieve higher efficiency, gain, and diversity performance in a relatively compact size. The unit element planar monopole antenna has been designed within 6.15×5.13×0.8mm3 with a partial ground. Four unit element antenna was orthogonally arranged on alternating sides of the substrate plane with narrow inter-component spacing in the multiple input multiple output (MIMO) system. The integration of the double negative (DNG) metamaterial array on the antenna led to a cumulative improvement in the overall performance of the antenna, which includes gain, efficiency, and isolation. The minimum isolation of the antenna increased by 11 dB with substrate-loaded metamaterial. The proposed MIMO antenna model with substrate-loaded metamaterial demonstrates 8 GHz instantaneous bandwidth (33.1 GHz - 41.1 GHz), 0.001 envelope correlation coefficient (ECC), diversity gain (DG) greater than 9.99 dB, channel capacity loss (CCL) less than 0.2bits/s/Hz, and a total active reflection coefficient (TARC) of 25 dB, which suggests that the diversity characteristics of the MIMO antenna system is impressive. Moreover, a densely packed 12-element antenna model has been introduced in this study with 360∘ pattern diversity, capable of receiving signals from any direction. Three 4-element MIMO systems have been arranged in an architecture to develop the 12-element MIMO system, and the size of the 12-element MIMO architecture is 15×15×15mm3. Despite having this compact size and dense packing, the 12-element MIMO antenna model shows similar diversity performance as the 4-element antenna model. Analog equivalent circuit models or resistor-inductor-capacitor (RLC) equivalent systems for the antenna models were created. A concept of a 128-element massive MIMO antenna has been presented to support the end devices, creating an application scenario of an IoT-interconnected smart city.

Cryopreservation of human spermatozoa or testicular tissue for fertility preservation

Loss of reproductive capacity due to treatments for malignant or non-malignant diseases or even as aresult of diseases themselves significantly impacts patients' quality of life. Cryopreservation of sperm from ejaculate is awell-established procedure for preserving the fertility of these patients and thus improving their quality of life in the long term. If cryopreservation of sperm from ejaculate is not possible, either because ejaculation cannot occur or no sperm can be found in the ejaculate, the preferred treatment option is (microsurgical) testicular sperm extraction (mTESE). Testicular sperm and ejaculated spermatozoa can be cryopreserved and later used for intracytoplasmic sperm injection (ICSI) treatment. The use of cryopreserved sperm for fertility treatment does not carry an increased risk of malformations in the offspring. If gonadotoxic therapy is necessary in pre- or early pubertal boys, the only option to preserve fertility in the long term is to cryopreserve spermatogonial stem cells from testicular tissue as part of the Androprotect© network. This is an experimental approach which has been available since 2012 acrossGermany and which is accompanied by intensive scientific work ( www.androprotect.de ).

Study on Phase Change Materials' Heat Transfer Characteristics of Medium Temperature Solar Energy Collection System.

Within the next five years, renewable energy is expected to account for approximately 80% of the new global power generation capacity, with solar power contributing to more than half of this growth. However, the intermittent nature of solar energy remains a significant challenge to fully realizing its potential. Thus, efficient energy storage is crucial for optimizing the effectiveness and dependability of renewable energy. Phase-change materials (PCMs) can play an important role in solar energy storage due to their low cost and high volumetric energy storage density. The low thermal conductivity of PCMs restricts their use for energy storage, despite their immense potential. Hence, the primary goal of this study is to experimentally investigate the energy storage capacity of two blended phase-change materials (paraffin and barium hydroxide octahydrate) through integration with a medium-temperature solar heat collection system. The experimental findings reveal that the blended PCMs possess the highest cumulative charge fraction (0.59), energy capacity, and low energy loss compared to each PCM alone. Furthermore, the phase change storage tank achieves higher heat storage (27%) and exergy storage efficiency (18%) compared to the stored tank water without any PCMs. The blended PCMs enhanced their performance, exhibiting improved interaction and excellent thermal storage properties across a range of temperatures, offering an opportunity for the design of an energy-efficient, low-cost storage system.

Achieving High Stability and Capacity in Micron-Sized Conversion-Type Iron Fluoride Li-Metal Batteries.

Iron fluoride, a conversion-type cathode material with high energy density and low-cost iron, holds promise for Li-ion batteries but faces challenges in synthesis, conductivity, and cycling stability. This study addresses these issues by synthesizing micron-sized iron-fluoride using a simple solid-state synthesis. Despite a large particle size, a high capacity of 571mAhg-1 is achieved, which is attributed to the unique surface and internal pores within the iron-fluoride particles, which provided a large surface area. This is the first study to demonstrate the feasibility of using large iron fluoride particles to enhance the energy density of the electrode and achieve an iron fluoride full cell with high capacity. Also, the cause of the capacity fading is investigated. Electrode delamination from the current collector, which is the main cause of capacity fading in early cycles, is resolved using a carbon-coated aluminum (C/Al) current collector. Moreover,iron (Fe) dissolution and the deposition of dissolved Fe on the Li metal also contributed significantly to the degradation. Localized high-concentration electrolytes (LHCEs)suppress iron dissolution and Li dendrite growth, resulting in long-cycle stability for 300 cycles. This study provides insights into the further development of conversion-type metal fluorides across various compositions.

Solid‐State Revolution: Assessing the Potential of Solid Polymer Electrolytes in Lithium‐Ion Batteries

AbstractLithium‐ion batteries (LIBs) are crucial for achieving sustainable energy goals due to their high energy density and long cycle life. They dominate markets like consumer electronics, electric vehicles, and stationary energy storage systems. However, current LIBs use liquid electrolytes, which are toxic, flammable, and their liquid state does not resist dendrite growth, causing battery capacity decline and failure. Additionally, the limited availability of lithium and other metals makes liquid‐based LIBs less sustainable. On the other hand, solid polymer electrolytes (SPEs) offer a safer alternative as they are non‐volatile and can resist dendrite growth. However, ion transport in solids is much more restricted than in liquids, while imperfect solid‐solid interfaces contribute to interfacial resistance leading to lower ionic conductivity and increasing Ohmic losses or requiring battery operation at elevated temperatures. Chemical and mechanical degradation of these interfaces can also result in battery capacity fade, and poorer cyclic performance compared to liquid electrolytes. Understanding the ionic transport mechanisms in SPEs is critical for designing and optimizing the nanostructure of polymers and polymer/electrode interfaces to overcome these limitations. In this review, the fundamental mechanisms of ion transport in SPEs will first be explored. Various state‐of‐the‐art approaches for addressing the key challenges in SPEs and their solutions are then discussed. Furthermore, the current status of SPEs is analyzed to determine their potential for replacing liquid electrolytes in the future.

Thirty two port super wideband diversity antenna for indoor communications

This paper introduces a novel design featuring a thirty-two port diversity antenna with an elliptical shape, fed by an asymmetric coplanar waveguide (CPW). The antenna incorporates uneven meander lines, tailored for super-wideband (SWB) applications. The structure of the unit cell is of an elliptical patch with an elliptical slot, and it is connected to a rectangular stub and asymmetric meander line. The size of the single element is 22 mm × 20 mm, and it operates from 3 to 40 GHz. The bandwidth dimension ratio of the unit cell is 3911, bandwidth ratio is 13.33:1, and fractional bandwidth is 172.09%. The single element is developed into a 3-D thirty-two port diverse antenna, composed of a horizontal plane and four planes perpendicular to it. The diverse antenna has a peak gain of 12.5 dBi and an efficiency of 94%. The computed envelope correlation coefficient (ECC), as determined using S-parameters and far-field measurements, is less than 0.1. The attained diversity gains (DGs) of the developed MIMO antenna are above 9.9 dB in terms of both S-parameter and far-field computations. The obtained thirty-two port diverse antenna channel capacity loss (CCL) is below 0.25 bits/s/Hz. The mean effective gain (MEG) of the constructed thirty-two port antenna is below 2. To validate the appropriateness of the developed thirty-two port antenna for wireless indoor environment, an enclosure made of acrylonitrile butadiene styrene (ABS) is crafted and fabricated, and the characteristics of the proposed diverse antenna are investigated.

Development and characterization of mesoporous silica-MgSO4-MgCl2 binary salt composites for low-grade heat storage in fluidized bed systems

Achieving nearly zero-energy buildings requires the efficient utilization and storage of renewable energy. Salt-hydrate-based thermochemical energy storage (TCES) systems are promising due to their high heat storage capacity and minimal seasonal heat loss. However, challenges remain in their commercialization and large-scale application. For instance, TCES systems using magnesium sulphate (MgSO4) provide low temperature lifts due to slow reaction kinetics. Incorporating deliquescent salts like magnesium chloride (MgCl2) can enhance sorption performance but may introduce stability issues such as agglomeration and decomposition. This study presents a novel binary-salt composite combining MgSO4 and MgCl2 within commercial mesoporous silica (CMS) to address these challenges and enhance overall performance. The binary-salt composite powder, with a particle size range of 150–300 μm, is well-suited for use in fluidized-bed reactors, where fast mass and heat transfer promote efficient moisture adsorption, prevent uneven temperature distribution, and reduce agglomeration. Thermogravimetric analysis (TGA) was employed to evaluate the water sorption and desorption behaviour of MgCl2-MgSO4@CMS binary-salt composites with a total salt content of 50 wt% and salt mixing ratios of 3:1, 1:1, and 1:3. The corresponding water sorption capacities were 0.95, 0.68, and 0.57 g/g, respectively. In comparison, the MgSO4@CMS single-salt composite showed a lower water adsorption capacity of 0.47 g/g and required temperatures exceeding 150 °C for complete regeneration. Reactor-scale experiments demonstrated that the MgCl2-MgSO4@CMS composite with a 1:1 salt mixing ratio could be fluidized at low gas velocities on the order of 10−2 m/s, achieving a maximum temperature lift of 24.7 °C and an energy density of 1018 kJ/kg during hydration at 80% relative humidity and 30 °C. Additionally, the binary-salt composite showed good cyclic stability with less particle agglomeration compared to the MgCl2@CMS single-salt composite.

Regulating the Spin‐State of Cobalt in Three‐Dimensional Covalent Organic Frameworks for High‐Performance Sodium‐Iodine Rechargeable Batteries

Although the catalytic activity is heavily reliant on the electronic structure of the catalyst, understanding the impact of electron spin regulation on electrocatalytic performance is still rarely investigated. This work presents a novel approach involving the single‐atom coordination of cobalt (Co) within metalloporphyrin‐based three‐dimensional covalent organic frameworks (3D‐COFs) to facilitate the catalytic conversion for sodium‐iodine batteries. The spin state of Co is modulated by altering the oxidation state of the porphyrin‐centered Co, achieving optimal catalysis for iodine reduction. Experimental results demonstrate that CoII and CoIII are incorporated into the 3D‐COFs, exhibiting spin ground states of S = 1/2 and S = 0, respectively. The low spin state of CoIII is favorable to hybridize with the sp 3d orbitals of I3‐, thus facilitating the conversion of I3‐ to I‐. Density‐functional theory (DFT) calculations further reveal that the presence of CoIII enhances iodide adsorption and accelerates the formation of NaI in 3D‐COFs‐CoIII, thereby promoting its rapid kinetic behaviors. Notably, the I2@3D‐COFs‐CoIII cathode achieves a high reversible capacity of 227.7 mAh g‐1 after 200 cycles at 0.5 C and demonstrates exceptional cyclic stability, exceeding 2000 cycles at 10 C with a minor capacity fading rate of less than one 0.01% per cycle.

Regulating the Spin-State of Cobalt in Three-Dimensional Covalent Organic Frameworks for High-Performance Sodium-Iodine Rechargeable Batteries.

Although the catalytic activity is heavily reliant on the electronic structure of the catalyst, understanding the impact of electron spin regulation on electrocatalytic performance is still rarely investigated. This work presents a novel approach involving the single-atom coordination of cobalt (Co) within metalloporphyrin-based three-dimensional covalent organic frameworks (3D-COFs) to facilitate the catalytic conversion for sodium-iodine batteries. The spin state of Co is modulated by altering the oxidation state of the porphyrin-centered Co, achieving optimal catalysis for iodine reduction. Experimental results demonstrate that CoII and CoIII are incorporated into the 3D-COFs, exhibiting spin ground states of S = 1/2 and S = 0, respectively. The low spin state of CoIII is favorable to hybridize with the sp 3d orbitals of I3-, thus facilitating the conversion of I3- to I-. Density-functional theory (DFT) calculations further reveal that the presence of CoIII enhances iodide adsorption and accelerates the formation of NaI in 3D-COFs-CoIII, thereby promoting its rapid kinetic behaviors. Notably, the I2@3D-COFs-CoIII cathode achieves a high reversible capacity of 227.7 mAh g-1 after 200 cycles at 0.5 C and demonstrates exceptional cyclic stability, exceeding 2000 cycles at 10 C with a minor capacity fading rate of less than one 0.01% per cycle.

Monotonic and cyclic lateral loading of piles in low- to medium-density chalk

Offshore and other structures often rely on driven piles to carry lateral loads. However, there is currently no established design method to cover lateral loading at chalk sites, which are widespread across Northwest Europe. This paper reports monotonic and cyclic lateral load tests on highly instrumented 508 mm and 1220 mm diameter. open steel piles driven at a well-characterised chalk test site in Kent, UK, for a recent joint industry project that developed new benchmark datasets and analyses, supported by high-quality testing. The ultimate lateral pressures mobilised in the chalk are shown to be relatively low compared to its uniaxial compressive strengths (UCS) due to pile-driving damage, natural fracturing, local yielding and brittleness. Significant gaps opened between the piles and chalk during loading, that led to a substantially softer response on unloading and subsequent reloading, as well as marked axial capacity losses. Reaction curves extracted from the field measurements and applied in a one-dimensional numerical model perform well in reproducing the monotonic lateral tests. As with piles driven in other materials, one-way cyclic lateral loading led to permanent displacement accumulation and stiffness changes that were linked to the cyclic loading parameters. Both effects were more marked under biaxial cyclic lateral loading.

Contamination in LIB Pouch Cells Promoting Self‐Discharge and Crosstalk

AbstractStorage studies of lithium‐ion battery electrolyte within bags made of commercial pouch foils, commonly used as encasing material of battery cells, revealed the presence of contamination leaching from the pouch foil material into the electrolyte. By analyzing the stored electrolyte via GC‐MS the appearing compound was identified as 2,4‐di‐tert‐butylphenol (2,4‐DTBP). To investigate the influence of DTBP on the battery cell performance, full cells employing commercial LiNi1/3Mn1/3Co1/3O2 based cathodes and graphite‐type anodes were assembled using 1 M LiPF6 in ethylene carbonate/ dimethyl carbonate mixture as the electrolyte with/out the intentional addition of either 2,4‐DTBP or its constitutional isomer 2,6‐DTBP. Furthermore, dimethyl terephthalate (DMT), a literature known redox shuttle triggering impurity leaching from PET‐based fixing tape used in LIBs, was added to compare the effect of DMT to DTBPs. It was revealed that either DTBP contaminations have a significant impact on the self‐discharge behavior of the studied cells, which exceed the effect of present DMT. Moreover, all contaminants heavily increase transition metal dissolution‐migration‐deposition (TM DMD) processes and irreversible capacity loss. When vinylene carbonate, an SEI forming additive, is added to the electrolyte mixtures self‐discharge, as well as TM DMD are suppressed to a different degree depending on the type of contaminant added.

Sensitivity of Capacity Fade in Vanadium Redox Flow Battery to Electrolyte Impurity Content.

The gradual capacity decrease of vanadium redox flow battery (VRFB) over long-term charge-discharge cycling is determined by electrolyte degradation. While it was initially believed that this degradation was solely caused by crossover, recent research suggests that oxidative imbalance induced by hydrogen evolution reaction (HER) also plays a significant role. In this work by using vanadium pentoxides with different impurities content, we prepared three grades of vanadium electrolyte. By measuring electrochemical properties on carbon felt electrode in three-electrode cell and VRFB membrane-electrode assembly we evaluate the influence of impurity content on battery polarization and rate of side reactions which is indicated by the increase of average oxidation state (AOS) during charge-discharge tests and varies from 0.061 to 0.027 day-1 for electrolytes made from 99.1 and 99.9 wt % V2O5. We found that increase of AOS correlates with the increase of open-circuit voltage of VRFB in the discharged state ranging from 9.6 to 14.9 mV day-1 for highest and lowest electrolyte purity levels, respectively. While AOS increase is significant, it does not solely determine capacity fade. It is demonstrated that the presence of vanadium crossover decreases capacity fade, i. e. levels the contribution of side reactions on capacity drop.

Lithium Demand and Cyclability Trade‐Off in Conductive Nanostructure Scaffolds in Terms of Different Tortuosity Parameters

AbstractThrough alteration of the polarity of DC plasma during the growth of carbon nanotubes in a PECVD reactor, significantly different morphologies of such species have been achieved. By using this approach, for the first time, both Half‐aligned and Entangled structures were synthesized, along with Full‐aligned carbon nanotubes, introducing three binder‐free electrodes with various levels of tortuosity. The crucial parameter and influential effect of tortuosity in these three‐dimensional nanostructure scaffolds for application in lithium‐ion batteries were investigated. Previous research findings suggested that increasing the tortuosity of the conductive scaffolds leads to preferential accumulation of lithium at the top surface and causes the loss of capacity in subsequent charge‐discharge cycles. Our finding reveals that there exists a trade‐off between lithium‐demand, capacity, and preferential accumulation of lithium at the top surface. Among the presented scaffolds, the Half‐aligned MWCNTs was able to maintain a high capacity of 876.9 mAh/g over more than 300 cycles, and demonstrate capacity improvement during this period and excellent rate capability, even at a rate of 5 C. This capacity is almost three times that can be achieved with graphite, showcasing promising and outstanding results for carbon nanotubes.