Hydrogen Content Research Articles

Implementation of a finite element framework coupling chemo‐mechanics and the Gurson‐Tvergaard‐Needleman model

AbstractHydrogen embrittlement in ductile metals, such as steel, is a significant concern, for instance, in the safety assessment of existing pipeline infrastructure intended for hydrogen transport. The ductile damage mechanism in steels is characterized by the nucleation, growth, and coalescence of microvoids, which is further enhanced by the presence of hydrogen. This leads to material damage and premature failure in components. Mechanisms contributing to hydrogen‐induced reduction of strength in steels include hydrogen‐enhanced decohesion (HEDE), hydrogen‐enhanced local plasticity (HELP), and hydrogen‐enhanced strain‐induced vacancies (HESIV). The HEDE mechanism leads to a principal stress‐controlled brittle failure mode. Conversely, the HELP and the HESIV mechanisms, which are dominated by plastic deformation, alter the ductile damage behavior as they lead to accelerated void growth and coalescence. Furthermore, interstitial diffusion of hydrogen leading to lattice expansion, commonly referred to as swelling, also contributes to hydrogen‐induced embrittlement. Hydrogen embrittlement is therefore a stress‐diffusion process that involves chemo‐mechanical coupling, where hydrogen atoms primarily diffuse toward areas with high hydrostatic stress. In this regard, we propose a framework using the finite element method and combining coupled chemo‐mechanics and the well‐known Gurson‐Tvergaard‐Needleman (GTN) damage model. The framework is motivated by mixed rate‐type potentials, that account for the influence of hydrogen concentration on the damage behavior. An additional dependence of the fracture strain and evolution of the void volume fraction on hydrogen is included. A comparison of the fully‐coupled model to simplified versions is conducted to individually assess the role of hydrogen concentration on damage evolution and the stress state on diffusion.

Evaluation of crack initiation load of silica glass surfaces formed during subcritical crack growth

AbstractThe crack initiation load of freshly fractured surfaces for silica glass was evaluated with ball indentation. The fracture surfaces were formed during subcritical crack growth in the regions I, II, and III of the stress intensity factor (KI)—crack velocity (V) curve. From the KI–V curve, we linked the obtained fracture surfaces with the ones in the regions I, II, and III. It was found that the crack‐forming probability was the lowest for the fracture surface formed in the region III of the KI–V curve. In order to understand the controlling factors of the crack formation, some properties which are topography, relative nonbridging oxygens (NBO), hydrogen concentrations, and Si–O three‐ or four‐membered ring structures, of the fracture surfaces were measured by atomic force microscopy, X‐ray photoelectron spectroscopy, dynamic secondary ion mass spectroscopy, and Raman spectroscopy, respectively. No distinct difference in NBO and hydrogen concentrations nor the ring structures were found among the fracture surfaces formed in different regions in the KI–V curve. The peak‐to‐valley height of the fracture surface, however, decreased with increasing crack velocity. It is concluded that the roughness or topography of the freshly fractured surface is one of the controlling factors which reduce the intrinsic strength of silica glass.

Efficient and emission-reduced recovery of high-purity copper from waste enameled copper wires

The escalating demand for refined copper intensifies research into the recycling of copper-based solid waste, exemplified by recovery of copper from waste enameled copper wires (WECWs). Despite its potential, the pyrolysis process for WECWs is hindered by embrittlement, diminishing both recycling yield and quality. Our study pioneers the elucidation of the embrittlement mechanism during WECWs pyrolysis through atom probe tomography and first-principles calculations, revealing that hydrogen, a byproduct of paint film pyrolysis, accumulates at copper grain boundaries, inducing embrittlement by reducing adhesion energy. We introduce two innovative strategies to mitigate hydrogen-induced embrittlement: vacuum pyrolysis and enhanced N2 flow. These approaches significantly reduced hydrogen content from 11.1 % to about 5 % and increased elongation from 2.65 % to 15 %. Moreover, pyrolysis efficiencies of 92.79 % and 91.4 % were achieved, respectively, at temperatures 50 °C lower than conventional methods. Our findings provide crucial theoretical insights into embrittlement and offer effective recovery strategies for copper from solid waste.

Very high cycle fatigue properties of ultrahigh strength steels in the presence of hydrogen

The very high cycle fatigue (VHCF) properties of 2000 MPa ultrahigh strength martensitic steels after hydrogen pre-charging were investigated by means of ultrasonic fatigue tests. Results showed that the VHCF lives of the experimental steels were drastically decreased by about two orders after pre-charged with a hydrogen concentration of CH = 1.23 wppm. The experimental steel tempered at a higher temperature of 300 °C with some epsilon-carbides and a lower density of dislocations showed higher VHCF lives in the presence of hydrogen. It could be attributed to the lower hydrogen diffusion coefficient since hydrogen might accelerate fatigue crack propagation in the granular bright facet (GBF) area.

Carbonization and Gasification of Cow‐Dung and Fe3O4 Nanoparticles at Different Operating Conditions for Hydrogen Production

AbstractCow dung is an abundant agricultural by‐product that poses disposal challenges. Converting this waste into a valuable energy resource aligns with sustainable waste management practices and contributes to a circular economy. This research aims at Cow dung disposal by carbonization and gasification for hydrogen generation and maximizes it by optimizing the process parameters. In the pyrolysis‐carbonization process, the influence of temperature on cow dung and its biochar characteristics was initially investigated. On the cow dung feedstock, different operating temperatures at about 400, 500, and 600 °C and response times of about 30, 60, and 120 min were tested. With CD450 as the feedstock, the gas concentrations and hydrogen yield were around 62 vol% and 0.69 m3 kg−1, respectively, for longer reaction times. Similar to this, the gas concentration and yield value for hydrogen at 600 °C gasification temperature is around 64 vol% and 0.91 m3 kg−1. Cow dung is evidently acceptable for larger hydrogen production at higher gasification temperatures and reaction times when the carbonization temperature is 450 °C. In addition, when compared to feedstock without adding nanoparticles, including Fe3O4 nanoparticles may increase the hydrogen concentration and yield by around 13.5 % and 4.21 %, respectively.

Influence of hydrogen on the elastic properties and dislocation behavior in Fe–Cr and Fe–Ni alloys by DFT calculations

The effect of interstitial hydrogen on the elastic properties of bcc Fe, bcc Fe–Cr, and bcc Fe–Ni was investigated using density functional theory calculations. Our results indicate that the elastic moduli decrease linearly with increasing hydrogen concentration. The consequences of hydrogen for the mechanical properties of bcc Fe, bcc Fe–Cr, and bcc Fe–Ni were analyzed, considering various factors such as the ideal shear stress, Peierls stress, number of dislocation pile-ups, and critical crack growth lengths. At the same hydrogen concentration, compared to the bcc Fe and bcc Fe–Ni systems, fewer dislocation pile-ups and shorter critical crack growth lengths can facilitate the nucleation and propagation of cracks in the bcc Fe–Cr system. Finally, we propose a mechanism to explain the influence of Cr and Ni on hydrogen embrittlement.

Study on the role of alkali halides on the mutarotation and dehydration of d-xylose in aqueous solution

Although the xylose mutarotation and transformation have been investigated largely separately, their relationship has been rarely systematically elaborated. The effect of several factors such as xylose concentration, temperature, and salt concentration, affecting the mutarotation of xylose are discussed. Nine alkali halides (LiCl, NaCl, KCl, LiBr, NaBr, KBr, LiI, NaI, and KI) are used to test salt effects. The relationship between xylose rotation rate constant (kM), specific optical rotation at equilibrium ([α]eqm), α/β ratio, H chemical shift difference (ΔΔδ), Gibbs free energy difference (ΔG), hydrogen ion or hydroxide ion concentration ([H+] or [OH−]), and xylose conversion is discussed. Different salts dissolved in water result in different pH of the solutions, which affect the mutarotation of xylose, with the nature of both cation and anion. Shortly, the smaller the cation radius is and the larger the anion radius is, the greater the mutarotation rate is. In the dehydration of xylose to furfural in salty solutions, xylose conversion is positively correlated to mutarotation rate, H+ or OH− concentration, and the energy difference between α-xylopyranose and β-xylopyranose. Although the [α]eqm of xylose is positively correlated with α/β configuration ratio, there is no obvious correlation with xylose dehydration. The conversion to furfural in chlorides is superior to that in bromines and iodides, which is due to the fact that the pH of chloride salts is smaller than that of the corresponding bromide and iodized salts. Higher H+ concentration prefers to accelerate the formation of furfural. In basic salt solutions, the xylulose selectivity is higher than that of furfural at the initial stage of reaction. The furfural selectivity and carbon balance are better in acidic condition rather than in basic condition. In H2O-MTHF (2-Methyltetrahydrofuran) biphasic system, the optimal furfural selectivity of 81.0 % is achieved at 190 °C in 1 h with the assistance of LiI and a little HCl (0.2 mmol, 8 mmol/L in aqueous phase). A high mutarotation rate represents rapid xylose conversion, but a high furfural selectivity prefers in acidic solutions, which would be perfect if organic solvents were available to form biphasic systems.

Hydrogen-releasing magnesium hydrogel mitigates post laminectomy epidural fibrosis through inhibition of neutrophil extracellular traps

Epidural fibrosis is a primary contributor to the failure of laminectomy surgeries, leading to the development of failed back surgery syndrome (FBSS). Post-laminectomy, neutrophils infiltrate the surgical site, generating neutrophil extracellular traps (NETs) that contribute to epidural fibrosis. Reactive oxygen species (ROS) play a pivotal role in mediating NETs formation. Molecular hydrogen, recognized for its selective antioxidant properties and biosafety, emerges as a potential therapeutic gas in suppressing epidural fibrosis. In this study, we developed an in-situ hydrogen release hydrogel that inhibits the formation of NETs and mitigates epidural scarring. Biodegradable magnesium (Mg) microspheres served as a hydrogen source, coated with PLGA to regulate hydrogen release. These microspheres (Mg@PLGA) were then incorporated into a PLGA-PEG-PLGA thermosensitive hydrogel (Mg@PLGA@Gel), providing a surgical implant for sustained, long-term hydrogen release. In vitro experiments confirmed the biocompatibility of the system, demonstrating that hydrogen produced by Mg@PLGA effectively neutralizes neutrophil intracellular ROS and inhibits NETs formation. Histological analyses, including H&E staining, MRI, Masson staining, and immunohistochemistry, collectively indicate that Mg@PLGA@Gel is biocompatible and effectively inhibits epidural fibrosis post-laminectomy. Furthermore, Mg@PLGA@Gel inhibits ROS accumulation and NETs formation at the surgical site. These findings suggest that Mg@PLGA@Gel ensures continuous, therapeutic hydrogen concentration, providing relief from epidural fibrosis in a laminectomy mouse model. Statement of significance•The hydrogen-releasing hydrogel combines the therapeutic effects of a physical barrier with immunomodulation.•In situ-generated molecular hydrogen scavenges ROS caused by surgical stress and suppresses NETs formation.•The hydrogen-releasing hydrogel is demonstrated to exhibit high biocompatibility and inhibit epidural scar formation in vivo.

Surrogate model-based assessment of particle damage behaviour of Al[sbnd]Zn[sbnd]Mg alloy

Recent research has found some intermetallic compound particles with even stronger hydrogen trapping capacity (e.g., Al7Cu2Fe) than the age-hardening precipitates that are reported to be the origin of hydrogen embrittlement in aluminium. Such intermetallic compound particles can reduce hydrogen concentration at the interface between the precipitates and aluminium by absorbing hydrogen in their interiors, thus preventing the hydrogen embrittlement of aluminium. However, this cannot be achieved if the particles, which have absorbed large amounts of hydrogen, are damaged due to hydrogen embrittlement. In this study, the hydrogen embrittlement of aluminium was observed in situ by X-ray CT, and the damage behaviour was analysed of all the particles that were located in the gauge section of a single tensile specimen. After exhaustive quantification of the size, shape, and spatial distribution of the particles, coarsening processes identified highly correlated design variables. Subsequently, particle damage behaviour was analysed utilizing a surrogate model using a support vector machine. The damage to Al7Cu2Fe particles could be described only by design variables representing size and shape, while those representing spatial distribution were removed through the coarsening processes. No change was observed in the damage behaviour of Al7Cu2Fe particles with increasing hydrogen concentrations, and it was concluded that the dispersion of Al7Cu2Fe particles is effective in preventing hydrogen embrittlement of aluminium. The contribution of damaged particles to the formation of fracture surfaces and the damage behaviour of Mg2Si particles, where damage is accelerated by hydrogen, were also analysed.

Photosynthesizing carbonate/nitrate into Chlorococcum humicola biomass for biodiesel and Bacillus coagulans-based biohydrogen production

Biofuel can be generated by different organisms using various substrates. The green alga Chlorococcum humicola OQ934050 exhibited the capability to photosynthesize carbonate carbon, maybe via the activity of carbonic anhydrase enzymes. The optimum treatment is C:N ratio of 1:1 (0.2 mmoles sodium carbonate and 0.2 mmoles sodium nitrate) as it induced the highest dry mass (more than 0.5 mg.mL−1). At this combination, biomass were about 0.2 mg/mL−1 carbohydrates, 0.085 mg/mL−1 proteins, and 0.16 mg/mL−1 oil of this dry weight. The C/N ratios of 1:1 or 10:1 induced up to 30% of the Chlorococcum humicola dry mass as oils. Growth and dry matter content were hindered at 50:1 C/N and oil content was reduced as a result. The fatty acid profile was strongly altered by the applied C.N ratios. The defatted leftovers of the grown alga, after oil extraction, were fermented by a newly isolated heterotrophic bacterium, identified as Bacillus coagulans OQ053202, to evolve hydrogen content as gas. The highest cumulative hydrogen production and reducing sugar (70 ml H2/g biomass and 0.128 mg/ml; respectively) were found at the C/N ratio of 10:1 with the highest hydrogen evolution efficiency (HEE) of 22.8 ml H2/ mg reducing sugar. The optimum treatment applied to the Chlorococcum humicola is C:N ratio of 1:1 for the highest dry mass, up to 30% dry mass as oils. Some fatty acids were induced while others disappeared, depending on the C/N ratios. The highest cumulative hydrogen production and reducing sugar were found at the C/N ratio of 10:1.

Atomic effect and mechanism of different hydrogen content on superlubricity properties of H-DLC films

Hydrogen atoms play a pivotal role in achieving superlubricity in DLC films. Nevertheless, the inherent limitations in analytical testing techniques obscure the mechanisms by which hydrogen atoms achieve superlubricity in DLC films. Furthermore, direct evidence supporting the widely accepted mechanism of hydrogen passivation remains elusive. Therefore, we used ReaxFF MD simulations to investigate the effects of different hydrogen content on the tribological and wear properties of hydrogen-doped H-DLC films. Hydrogen atoms diffuse from the DLC films and gradually accumulate on the friction surface during the sliding, effectively passivating and inhibiting the C–C bonds at the interface. This reduces cross-linking between H-DLC films, consequently loweringfrictiontemperature significantly during the sliding. A significant release of hydrogen atoms during the friction process weakens the strength of machinery of H-DLC films, potentially causing structural failures under hydrogen-rich conditions, with the released hydrogen atoms subsequently occupying structural voids within films. At the microscopic scale, the friction of H-DLC film decreases with the increase of hydrogen content, but when the hydrogen content reaches 40 % or above, the local collapse of the system will be caused, resulting in the failure of superlubricity. Finally, the friction and wear of H-DLC film under high hydrogen conditions will rebound.

The Determination of Woody Biomass Resources and Their Energy Potential from Hazelnut Tree Cultivation

The aim of this study was to estimate the shoot weight of four selected hazelnut cultivars and to see if the morphological characteristics of the cultivar and the age of the shoots affect their quality when used as fuel. This study shows that the cultivar ‘Olga’ generated the highest amounts of woody biomass (6507 t·ha−1), while ‘Olbrzymi z Halle’ generated the lowest (3843 t·ha−1). ‘Olbrzymi z Halle’ had the highest calorific values (HHVs) (18.08 MJ·t·ha−1 for annual shoots and 18.03 MJ·kg−1 for perennial shoots) and ‘Olga’ had the lowest calorific values (16.64 MJ·kg−1 for annual shoots and 16.39 MJ·kg−1 for perennial shoots). The age of the shoots had a minimal effect on the chemical and energy parameters. Emissions were the highest for ‘Olbrzymi z Halle’ (CO: 57.74 MJ·kg−1 for perennial shoots, CO2: 1414.05 MJ·kg−1) and lowest for ‘Olga’ (CO: 50.57 MJ·kg−1, CO2: 1238.46 MJ·kg−1). The cultivar ‘Olbrzymi z Halle’, which generated the least amount of biomass compared to the other cultivars, stands out for its high energy value due to its low moisture and ash contents and its high carbon and hydrogen contents, making it attractive for the purposes of biofuel production and supporting sustainable agriculture. The practical implications of the research findings include the selection of suitable varieties for biofuel production, the management of biomass moisture content, and the optimisation of combustion techniques to reduce emissions. The potential for using hazelnut shoots as a biofuel highlights the importance of sustainable agriculture and renewable energy production. The results provide valuable information that can support decisions regarding the cultivation and use of hazelnut shoots for biofuel production while minimising negative environmental impacts.

Effects of hydrogen addition on ignition characteristics and engine performance of ammonia-hydrogen blended fuel: A kinetic analysis

To investigate the effects of hydrogen addition on the ignition characteristics and engine performance of ammonia-hydrogen fuel, a reaction kinetics mechanism suitable for high-pressure engine conditions was proposed. The study explores the influence of hydrogen blending ratios on the ignition delay time (IDT) of ammonia-hydrogen fuel, revealing the sensitive reactions and evolution characteristics of reaction pathways during the ignition process of ammonia-hydrogen fuel promoted by hydrogen. The study also investigates the impact of hydrogen blending ratios on the engine performance of ammonia-hydrogen fuel. The results show that the IDT of ammonia significantly decreases with increasing hydrogen blending ratios and temperature. The addition of hydrogen to ammonia significantly lowers the autoignition temperature boundary of the mixture. Under low-temperature and low-pressure conditions, ammonia, which would not ignite originally, ignites due to the addition of hydrogen. The addition of hydrogen shifts the sensitive reactions of the mixture from NH3 and NH2-related reactions to H2/O2-related reactions, without altering the reaction pathway of ammonia, only changing the pathway flux of components such as NH2, H2NN, H2NO, and HONO. In a spark-ignition (SI) engine, maintaining the total fuel heat value and ignition timing constant, an increase in hydrogen blending ratio significantly raises the peak cylinder pressure. However, due to the forward movement of the heat release process, the power performance of engine experiences varying degrees of reduction. Therefore, it is necessary to delay the ignition timing of engine with the increase in hydrogen blending ratio, moving the combustion center beyond the top dead center (TDC). Furthermore, increasing the hydrogen concentration in the blend significantly raises the temperature and pressure during the engine combustion process, leading to an increase in the concentration of thermal NOX in the emissions.

Investigating the Fatigue Response of Cathodically Charged Cold-Finished Mild Steel to Varied Hydrogen Concentrations

This study investigates the fatigue behavior of cold-finished mild steel subjected to electrochemical hydrogen charging under controlled conditions. Samples were subjected to hydrogen charging at constant time in a fixed electrolyte pH, after which the samples underwent fatigue testing under constant loading condition with fixed frequency. The primary objective was to assess the impact of varying hydrogen permeation levels on the number of cycles to failure. The experimental results revealed a complex relationship between hydrogen concentration and fatigue life. Initially, as hydrogen permeation increased, the number of cycles to failure substantially decreased, demonstrating the detrimental effect of diffused hydrogen on the fatigue resistance of samples. This decline in fatigue life was attributed to hydrogen embrittlement (HE) and hydrogen-enhanced decohesion (HEDE) phenomena, which collectively facilitate crack initiation and propagation. However, at high hydrogen concentrations, an unexpected increase in the number of cycles to failure was observed suggesting the existence of a threshold hydrogen concentration beyond which the fatigue mechanisms may be altered, potentially due to a saturation of hydrogen-related defects and mechanisms such as hydrogen-enhanced localized plasticity (HELP). The discovery from this research has significant implications for the material’s application in hydrogen-rich environments, such as those encountered in the energy and transportation industries.

Effect of heat input on the microstructure and hydrogen embrittlement susceptibility of the coarse-grain heat-affected zone of CrMo steels generated using a Gleeble 3500 welding simulator

The changes in microstructure and hydrogen embrittlement (HE) susceptibility of the simulated coarse-grain heat-affected zone (CGHAZ) of CrMo steels under three distinct heat input conditions were investigated. The cooling time from 800 °C to 500 °C, represented by t8/5, increased from 100 s to 200 and 400 s.. The sample with t8/5 = 100 s has a microstructure consisting of martensite and a small amount of lower bainite. When the t8/5 was increased to 200 s and 400 s, the HAZ consisted of 65.43 % martensite and 34.57 % lower bainite and 4.53 % martensite with 95.47 % bainite, respectively. The HE susceptibility was assessed by slow strain rate tensile (SSRT) testing of hydrogen-charged samples, and the HE susceptibility index (IHE) declined from 87.89 % to 61.37 % when t8/5 increased from 100 to 400 s. The high dislocation density and hydrogen concentration in the sample with t8/5 = 100 s led to intergranular fracture and incresaed HE susceptibility. The martensite lath and cementite/ferrite interface are the sites of crack initiation in the sample with t8/5 = 200 s. In the sample with a cooling time of 400 s, the martensite/ferrite interfaces are the main crack initiation sites under hydrogen charging.

Fluorescence of Atomic Hydrogen in Aqueous Media

It is shown that aqueous solutions of atomic hydrogen fluoresce under the action of UV irradiation. It is also shown that the spectra of this fluorescence have peaks whose maxima are close to the 5th and 6th lines of the Balmer series. All this made it possible to propose using this fluorescence to determine the concentration of atomic hydrogen in aqueous media, which seems relevant for both hydrogen energy and medicine. In addition, the possible involvement of this fluorescence in such phenomena as the blueness of the daytime sky, Cherenkov radiation and the Kirlian aura is analyzed here.

Numerical Analysis of Hydrogen-Enriched Natural Gas on Combustion and Emission Characteristics

AbstractThe integration of hydrogen into natural gas infrastructure presents a viable strategy for mitigating greenhouse gas emissions and advancing toward carbon neutrality. This study investigates the combustion characteristics and emissions profiles of hydrogen-enriched natural gas mixtures, specifically focusing on the composition of Russian pipeline natural gas. A comprehensive mathematical model was developed to predict emission concentrations and simulate fuel mixture combustion using MATLAB Simulink software. This versatile model facilitates further analysis within the MATLAB ecosystem. The simulation results demonstrate a significant correlation between the hydrogen content in the natural gas mixture and the resulting heat power output. With a constant fuel consumption rate, a notable decrease in heat power was observed as the hydrogen concentration increased, reaching a maximum reduction of 44.9% at a 45% hydrogen content. These findings underscore the feasibility of partially substituting natural gas with hydrogen, while also highlighting the necessity for increased fuel flow rates to maintain equivalent power output levels. This poses additional challenges for natural gas grid operators, necessitating infrastructure adaptations to accommodate higher fuel demands. The insights gained from this research contribute to the growing body of knowledge surrounding hydrogen integration in the energy sector, offering valuable implications for decarbonization strategies and the optimization of natural gas infrastructure.

Addressing Soil Acidity Challenges: Promoting Tea Production as Alternative Crop in Ethiopia -- Review

The prevalence of acidic soils in Ethiopia presents a significant obstacle to improving agricultural productivity and restricts the implementation of sustainable farming practices that could enhance food security. Acidic soils are typically defined by their high concentration of hydrogen ions and a lack of essential nutrients, which collectively create an environment that is less conducive to the growth of many vital staple crops. Consequently, farmers faced with these conditions often struggle to achieve optimal yields, which exacerbates food scarcity and undermines economic stability. To effectively combat the issues posed by acidic soils, it is imperative to adopt targeted soil management strategies that are specifically designed to address these challenges. This may include the implementation of soil reclamation techniques that aim to neutralize soil acidity and restore nutrient balance. Additionally, comprehensive initiatives must be undertaken to promote agricultural resilience, which could involve the cultivation of alternative crops that are better suited to thrive in acidic conditions, such as tea. This paper aims to provide a thorough examination of several key aspects related to the development and management of acidic soils in Ethiopia. It will investigate into the processes that contribute to the formation of acid soils, as well as the various types of acid soil present in the country, explore the distribution of acidic soils throughout Ethiopia, highlighting areas that are particularly affected and the implications for local farming practices. Furthermore, the analysis will address the specific impact of soil acidity on crop growth, yield, and quality. It will investigate how soil acidity influences the availability of essential nutrients for plants, thereby affecting the overall health and productivity of crops grown in these conditions. The promotion of tea production in Ethiopia is another critical topic that tea cultivation not only offers a viable alternative crop but also presents opportunities for economic development and diversification in agricultural systems. The mechanisms that confer aluminum resistance in tea plants will be discussed, as well as the ways in which aluminum can stimulate growth in these crops, thereby illustrating the unique resilience of tea plants in acidic environments. By addressing these complex issues holistically, the paper seeks to contribute valuable insights and foster a deeper understanding of how to navigate the challenges posed by acidic soils in the Ethiopian agricultural landscape.

Investigating the explosive characteristics of hydrogen/ n-butane blended fuel: Experimental and kinetic insights

Investigating the explosive characteristics of H2/n-C4H10 mixtures is crucial for the safe utilization of this blended fuel. Our study focused on varying equivalent ratios and hydrogen blending ratios within a closed 20-L spherical explosion vessel. Additionally, the microscopic kinetics of the reactions were analyzed through chemical reaction simulation. Our findings indicate that the most violent explosion occurred at an equivalent ratio of 1.2. Increasing hydrogen content intensified combustion reactions, reducing flame thickness and inducing cellular structures along the flame front. This escalation also increased explosion pressure, flame temperature, and flame propagation speed, elevating explosion risk. Moreover, the equilibrium molar fraction of O2 and CO2 decreased while that of H2O increased with higher hydrogen blending ratios. Correspondingly, the heat release rate and generation rates of H•, O•, and OH• radicals increased. Notably, the peak time of C2H4 and CH4 consumption rates preceded. Additionally, R5: O2 + H• = O• + OH• and R978: C4H10 + H• = SC4H9 + H2 represented crucial promoting and inhibiting steps, respectively. These insights deepen our understanding of the explosion mechanism of H2/n-C4H10 mixtures, providing a theoretical basis for designing safer protective measures and evaluating explosion risks in industrial production.

Quantifying concentration distributions in redox flow batteries with neutron radiography

The continued advancement of electrochemical technologies requires an increasingly detailed understanding of the microscopic processes that control their performance, inspiring the development of new multi-modal diagnostic techniques. Here, we introduce a neutron imaging approach to enable the quantification of spatial and temporal variations in species concentrations within an operating redox flow cell. Specifically, we leverage the high attenuation of redox-active organic materials (high hydrogen content) and supporting electrolytes (boron-containing) in solution and perform subtractive neutron imaging of active species and supporting electrolyte. To resolve the concentration profiles across the electrodes, we employ an in-plane imaging configuration and correlate the concentration profiles to cell performance with polarization experiments under different operating conditions. Finally, we use time-of-flight neutron imaging to deconvolute concentrations of active species and supporting electrolyte during operation. Using this approach, we evaluate the influence of cell polarity, voltage bias and flow rate on the concentration distribution within the flow cell and correlate these with the macroscopic performance, thus obtaining an unprecedented level of insight into reactive mass transport. Ultimately, this diagnostic technique can be applied to a range of (electro)chemical technologies and may accelerate the development of new materials and reactor designs.