Volumetric Effects Research Articles

Changes in Brain Structure and Function in a Multisport Cohort of Retired Female and Male Athletes, Many Years after Suffering a Concussion: Implications for Neuroplasticity and Neurodegenerative Disease Pathogenesis.

Cumulative effects of traumatic brain injury is of increasing concern, especially with respect to its role in the etiology and pathogenesis of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Compare regional brain volume and connectivity between athletes with a history of concussion and controls. We evaluated whole-brain volumetric effects with Bayesian regression models and functional connectivity with network-based statistics, in 125 retired athletes (a mean of 11 reported concussions) and 36 matched controls. Brain regions significantly lower in volume in the concussed group included the middle frontal gyrus, hippocampus, supramarginal gyrus, temporal pole, and inferior frontal gyrus. Conversely, brain regions significantly larger included the hippocampal and collateral sulcus, middle occipital gyrus, medial orbital gyrus, caudate nucleus, lateral orbital gyrus, and medial postcentral gyrus. Functional connectivity analyses revealed increased edge strength, most marked in motor domains. Numerous edges of this network strengthened in athletes were significantly weakened with concussion. Aligned to meta-analytic neuroimaging data, the observed changes suggest functional enhancement within the motor, sensory, coordination, balance, and visual processing domains in athletes, attenuated by concussive head injury with a negative impact on memory and language. These findings suggest that engagement in sport may benefit the brain across numerous domains, but also highlights the potentially damaging effects of concussive head injury. Future studies with longitudinal cohorts including autopsy examination are needed to determine whether the latter reflects tissue loss from brain shearing, or the onset of a progressive Alzheimer's disease like proteinopathy.

Effect of Injectable Acellular Adipose Matrix on Soft Tissue Reconstruction in a Murine Model

BackgroundThe extracellular matrix isolated from adipose tissue, known as acellular adipose matrix (AAM), represents a novel biomaterial. AAM functions as a scaffold that not only supports stem cell proliferation and differentiation but also induces adipogenesis and angiogenesis. This study aims to investigate the volumetric effects and microenvironmental changes associated with injectable AAM in comparison to conventional fat grafting.MethodsAAM was manufactured from fresh human abdominoplasty fat using a mechanically modified method and then transformed into an injectable form. Lipoaspirate was harvested employing the Coleman technique. A weight and volume study was conducted on athymic nude mice by injecting either injectable AAM or lipoaspirate into the scalp (n=6 per group). After eight weeks, graft retention was assessed through weight measurement and volumetric analysis using micro-computed tomography (micro-CT) scanning. Histological analysis was performed using immunofluorescence staining for perilipin and CD31.ResultsInjectable AAM exhibited similar weight and volume effects in murine models. Histological analysis revealed comparable inflammatory cell presence with minimal capsule formation when compared to conventional fat grafts. Adipogenesis occurred in both AAM-injected and conventional fat graft models, with no significant difference in the blood vessel area (%) between the two.ConclusionsIn summary, injectable AAM demonstrates effectiveness comparable to conventional fat grafting concerning volume effects and tissue regeneration in soft tissue reconstruction. This promising allogeneic injectable holds the potential to serve as a safe and effective “Off-the-Shelf” alternative in both aesthetic and reconstructive clinical practices.No Level AssignedThis journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Improved interfacial contact and electrochemical performance of highly Ni-rich LiNixCoyMn1-x-yO2 (x>90%) cathode in all-solid-state lithium battery

Single-crystal LiNixCoyMn1-x-yO2 (SC-NCM) cathodes design is an effective solution for enhancing electrochemical performance of all-solid-state lithium battery (ASSLBs). For highly Ni-rich SC cathode (Ni>90 %), the accumulation of local stress caused by anisotropic lattice shrinkage at deeply charging state is more destructive, and even SC-NCM design can not prevent the structure damage and interfacial contact failure between cathode and solid electrolyte (SE). In this work, small-size single-crystal design and Al-doping strategy are firstly combined to synthesize LiNi0.91Co0.04Mn0.04Al0.01O2 (S-SC-NCMA) cathode. Electrochemistry test, CP-SEM, GITT and in-situ EIS techniques are combined to reveal the interfacial evolution of cathode/SE. The kinetic limitation caused by local contact failure of cathode/SE and the formation of intergranular crack under high voltage are the main reason for capacity loss of ASSLBs. Small-size single-crystal design can reduce the volumetric strain effect and Al-doping strategy can further inhibit lattice shrinkage to improve contact. This work provides an effective cathode modification strategy for highly Ni-rich NCM (Ni>90 %) cathode to improve high-voltage performance of sulfide-based ASSLBs.

Comparative neuroimaging of sex differences in human and mouse brain anatomy

In vivo neuroimaging studies have established several reproducible volumetric sex differences in the human brain, but the causes of such differences are hard to parse. While mouse models are useful for understanding the cellular and mechanistic bases of sex-specific brain development, there have been no attempts to formally compare human and mouse neuroanatomical sex differences to ascertain how well they translate. Addressing this question would shed critical light on the use of the mouse as a translational model for sex differences in the human brain and provide insights into the degree to which sex differences in brain volume are conserved across mammals. Here, we use structural magnetic resonance imaging to conduct the first comparative neuroimaging study of sex-specific neuroanatomy of the human and mouse brain. In line with previous findings, we observe that in humans, males have significantly larger and more variable total brain volume; these sex differences are not mirrored in mice. After controlling for total brain volume, we observe modest cross-species congruence in the volumetric effect size of sex across 60 homologous regions (r=0.30). This cross-species congruence is greater in the cortex (r=0.33) than non-cortex (r=0.16). By incorporating regional measures of gene expression in both species, we reveal that cortical regions with greater cross-species congruence in volumetric sex differences also show greater cross-species congruence in the expression profile of 2835 homologous genes. This phenomenon differentiates primary sensory regions with high congruence of sex effects and gene expression from limbic cortices where congruence in both these features was weaker between species. These findings help identify aspects of sex-biased brain anatomy present in mice that are retained, lost, or inverted in humans. More broadly, our work provides an empirical basis for targeting mechanistic studies of sex-specific brain development in mice to brain regions that best echo sex-specific brain development in humans.

Comparative neuroimaging of sex differences in human and mouse brain anatomy.

In vivo neuroimaging studies have established several reproducible volumetric sex differences in the human brain, but the causes of such differences are hard to parse. While mouse models are useful for understanding the cellular and mechanistic bases of sex-specific brain development, there have been no attempts to formally compare human and mouse neuroanatomical sex differences to ascertain how well they translate. Addressing this question would shed critical light on the use of the mouse as a translational model for sex differences in the human brain and provide insights into the degree to which sex differences in brain volume are conserved across mammals. Here, we use structural magnetic resonance imaging to conduct the first comparative neuroimaging study of sex-specific neuroanatomy of the human and mouse brain. In line with previous findings, we observe that in humans, males have significantly larger and more variable total brain volume; these sex differences are not mirrored in mice. After controlling for total brain volume, we observe modest cross-species congruence in the volumetric effect size of sex across 60 homologous regions (r=0.30). This cross-species congruence is greater in the cortex (r=0.33) than non-cortex (r=0.16). By incorporating regional measures of gene expression in both species, we reveal that cortical regions with greater cross-species congruence in volumetric sex differences also show greater cross-species congruence in the expression profile of 2835 homologous genes. This phenomenon differentiates primary sensory regions with high congruence of sex effects and gene expression from limbic cortices where congruence in both these features was weaker between species. These findings help identify aspects of sex-biased brain anatomy present in mice that are retained, lost, or inverted in humans. More broadly, our work provides an empirical basis for targeting mechanistic studies of sex-specific brain development in mice to brain regions that best echo sex-specific brain development in humans.

Vitamin D and the Metabolic Phenotype in Weight Loss After Bariatric Surgery: A Longitudinal Study.

To evaluate the influence of vitamin D (VD) concentrations coupled with metabolic phenotypes preoperatively and 6months after Roux-en-Y gastric bypass (RYGB) on body variables and weight loss. A longitudinal, retrospective, analytical study comprising 30 adult individuals assessed preoperatively (T0) and 6months (T1) after undergoing Roux-en-Y gastric bypass. The participants were distributed preoperatively into metabolically healthy obese (MHO) and metabolically unhealthy obese individuals (MUHO) according to the HOMA-IR classification, as well as the adequacy and inadequacy of vitamin D concentrations in the form of 25(OH)D. All participants were assessed for weight, height, body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), visceral adiposity index (VAI), body circularity index (BCI), body adiposity index (BAI), weight loss, and assessment of 25(OH)D and 1,25(OH)2D concentrations using high-performance liquid chromatography with an ultraviolet detector (HPLC-UV). The statistical program used was SPSS version 21. VD adequacy and a healthy phenotype in the preoperative period may play an important role concerning body fat distribution, as the body averages for WHtR (0.020*) and BCI (0.020*) were lower in MHO participants. In comparison, those with VD inadequacy and MUHOs had higher BAI averages (0.000*) in the postoperative period. Furthermore, it is possible that VD inadequacy before and after RYGB, even in the presence of an unhealthy phenotype, may contribute to the increase in VAI values (0.029*) after this surgery. Only those with inadequate VD and MUHOs had higher 25(OH)D concentrations. Besides, this unhealthy phenotype had a greater reduction in BMI in the early postoperative period (p < 0.001). This study suggests that VD adequacy and the presence of a healthy phenotype appear to have a positive impact on the reduction of visceral fat in the context of pre- and postoperative obesity. In addition, there was a greater weight reduction in those with VD inadequacy and in MUHO, which suggests that the volumetric dilution effect of VD and catabolism after bariatric surgery is more pronounced in this specific metabolic phenotype.

Study of MOF‐derived Double Hemispherical Nano‐Co3O4/C Composite as Anode Material for Lithium‐Ion Batteries

AbstractCo3O4 emerges as a promising substitute in the field of anode electrode materials for the next‐generation of lithium‐ion batteries (LIBs). Nevertheless, challenges such as volumetric effects during cycling and insufficient conductivity have resulted in its subpar cycle stability, which impedes its practical application. In this study, we successfully employed a straightforward method to design and synthesize double hemispherical nano‐Co3O4/C composite materials derived from MOF‐74(Co). Benefiting from its nano‐porous structure combined with carbon materials, the resulting Co3O4/C electrode manifests outstanding electrochemical performance. Specifically, the obtained Co3O4/C electrode exhibits a notably high reversible cycle capacity (1151.9 mAh g−1 at 0.2 A g−1), exemplary rate capability, and outstanding long‐cycle performance (maintaining a capacity of 366.2 mAh g−1 at 1 A g−1 after 1400 cycles). This research introduces a novel approach for the development of innovative anode materials for LIBs.

Selective adsorption in ion exchange membranes: The effect of solution ion composition on ion partitioning

Electrodialysis is a water desalination technology that enables selective separation of ions, making it a promising solution for sustainable water reuse. The selectivity of the process is mainly determined by the properties of ion exchange membranes that can vary depending on the composition of ions in water, such as water uptake and charge density. In this work, we studied selective adsorption of Na+ and K+ ions in various ion exchange membranes considering the effect of solution ion composition on membrane water volume fraction. For that purpose, we conducted membrane adsorption experiments using solutions with Na+ and K+ ions with different ion compositions including Li+, Ca2+ or Mg2+ ions at different concentrations (0.001 – 0.25 M). The experiments showed that with the total ion concentration and the amount of divalent ions in solution, the membrane water volume fraction decreases while the selective adsorption of the smaller (hydrated) K+ ions over the Na+ ions in the membrane increases. We developed a theoretical framework based on Boublik-Mansoori-Carnahan-Starling-Leland (BMCSL) theory to describe the effect of membrane water volume fraction on selective adsorption of the ions by including volumetric effects, such as size exclusion. The developed framework was used to describe ion partitioning results of the membrane adsorption experiments. In addition, the effect of solution ion composition on selective ion removal during electrodialysis operation was evaluated using experimental data and theoretical calculations. The results of this study show that considering volumetric effects can improve the ion partitioning description in ion exchange membranes for solutions with various ion compositions.

Therapist versus Machine-Immediate Effects of Manual versus Mechanical Lymphatic Drainage in Patients with Secondary Lymphedema.

Background: Complex decongestive therapy (CDT) is the standard and basic therapy for lymphedema. The central component of CDT is manual lymphatic drainage (MLD). In addition to CDT, other measures such as intermittent pneumatic compression therapy (IPCT) (active compression machine therapy) are available. In this prospective research study, the objective and subjective effects of MLD and IPCT on lymphedema of the lower extremity were investigated and both therapies were directly compared. Furthermore, the patients' body mass index (BMI) and stage of lymphedema were tested for their effect on the respective therapy. Methods: Patients participating in the study received both therapies (MLD and IPCT) on the same lymphedema-affected limb at an interval of two days. The objective volumetric therapy effect was measured by the digital volume measurement of the affected limb. The subjective effects of the therapies were measured using two specially designed questionnaires. Results: A total of 40 patients were included in the study. There was no significant difference in the volume differences between the interventions, BMI categories, lymphedema, or treatment order regarding the immediate and two-day effect. Conclusions: No significant difference was found in the subjective or objective therapy efficacy of the two methods. Intermittent pneumatic compression therapy is considered a comparable therapeutic procedure when properly indicated.

Opposing effects of thyroid hormones on hypothalamic subunits and limbic structures in hyperthyroidism patients: A comprehensive volumetric study.

Thyroid hormones play a critical role in brain development, but paradoxically, patients with hyperthyroidism often exhibit cognitive decline and irritability. This study aims to explore the pattern of atrophy in hyperthyroid patients, changes in specific areas of the brain, including hypothalamic subfields and limbic structures, and their relationships with hormonal levels and psychometric tests. This prospective cross-sectional study involves 19 newly diagnosed, untreated hyperthyroid patients, and 15 age and gender-matched control subjects. The participants underwent psychometric and cognitive tests and volumetric MRI. The hypothalamic subfield (anterior-inferior, anterior-superior, superior-tubular, inferior-tubular, and posterior hypothalamus) and limbic structures (fornix, basal forebrain, nucleus accumbens, and septal nucleus) were segmented using voxel-based morphometry, surface-based morphometry, and deep learning algorithms. The groups were compared using the t-test, and correlation analyses were performed between clinical parameters and volumetric measurements. The correlation between hormonal parameters and volumetric measurements in patient and control groups was assessed with the Meng test. Hyperthyroid patients displayed widespread grey matter loss and sulcal shallowing in the left hemisphere. However, no local gyrification index changes or cortical thickness variations were detected. The limbic structures and hypothalamic subunits did not show any volume discrepancies. Free thyroxine in the patient group negatively correlated with bilateral anterior-inferior and right septal nucleus, but positively correlated with left anterior-inferior in the control group. Thyroid stimulating hormone in the patient group showed a positive correlation with bilateral fornix volume, a correlation absent in the control group. Disease duration negatively correlated with right anterior-inferior, right tubular inferior, and right septal nucleus. Changes in cognitive and psychometric test scores in the patient group correlated with the bilateral septal nucleus volume. Hyperthyroidism primarily leads to a reduction in grey matter volume and sulcal shallowing. Thyroid hormones have differing volumetric effects in limbic structures and hypothalamic subunits under physiological and hyperthyroid conditions.

Raman spectroscopy of active-carbon electrodes when Au colloids are placed at the electrolyte/electrode interface

Surface enhanced Raman spectroscopy (SERS) was used to study active-carbon (A-C) electrodes in super-capacitors cells; these electrodes were functionalized with Au nanoparticles (AuNPs). We observed a large enhancement in the cell's specific capacitance as a function of the AuNPs concentration. Cell capacitance is a volumetric effect while SERS is susceptible to the local number of colloids. The intensity ratio between the D-line (defect line) and the graphitic line (G-line), ID/IG, of the A-C electrode proved to be a good marker, independent of the measurement point. Rather than a peak, typical of amorphous films, this ratio has a dip at a particular AuNPs concentration, which is shifted upon the presence of the electrolyte. It is suggested that the seemingly unrelated phenomena - the capacitance enhancement and the intensity dip - are the result of the formation of a quasi-2D array of AuNPs at the interface between the electrolyte and the electrode.

SiO2/Co encapsulated in N-doped carbon nanofibers as anode materials for lithium-ion batteries

To address the issues of poor electrical conductivity and volume expansion of SiO2, the composite SiO2/Co encapsulated in N-doped Carbon nanofibers is prepared in situ using an electrostatic spinning method followed a high-temperature treatment. Co nanoparticles exist as an elementary substance in the composite and improve the electrical conductivity of the composite, resulting in enhanced electrochemical performance. In addition, the N-doped carbon nanofibers wrap around the outside of SiO2/Co to form a conductive network, which improves the conductivity of the composite and alleviates the volumetric effects during the charge-discharge process. As expected, the prepared SiO2/Co@N-doped carbon nanofibers exhibit excellent rate performance, which can provide a very high discharge specific capacity of 1276 mA h g−1 and 493 mA h g−1 at current densities of 0.1 A g−1 and 2 A g−1, respectively. The composite also has a long cycle life, with a reversible discharge capacity of 659 mA h g−1 at 0.5 A g−1 after 400 cycles, and 552 mA h g−1 at 1 A g−1 after 1000 cycles. Furthermore, a full-cell LiFePO4||SiO2|Co@N-doped carbon nanofibers can release a reversible capacity of 119 mA h g−1 at 0.1C.

A universal method for N/B codoped carbon bubbles for enhanced potassium ion storage

Carbon materials are widely regarded as highly promising anode materials for potassium ion batteries due to their features of tunable structure, affordable price, excellent conductivity, and favorable chemical stability. However, due to the sluggish potassium storage kinetics and relatively severe volumetric effect brought about by the large radius of potassium ions, carbon materials often suffer from unsatisfactory reversible capacity and weak rate performance. In this work, we propose to prepare a distinctive dual-atom doped carbon bubble material by a simple self-templating method. This unique structural design results in a high specific surface area, large layer spacing, abundant pore structure and enriched active sites. Owing to these merits, the N, B-doped carbon exhibits a high reversible capacity (534.0 mA h g−1 at 0.1 A g−1 after 200 cycles), long-term cycling stability and excellent rate capacity when used as the anode for potassium-ion batteries. The results of electrochemical kinetic studies indicate that capacitance control effects play a dominant role in the total energy storage mechanism. Furthermore, this preparation method has good generalizability and is expected to have applications in other batteries, supercapacitors or catalysis.

Unlocking the Design Paradigm of In-Plane Heterojunction with Built-in Bifunctional Anion Vacancy for Unexpectedly Fast Sodium Storage.

Transition metal chalcogenide (TMD) electrodes in sodium-ion batteries exhibit intrinsic shortcomings such as sluggish reaction kinetics, unstable conversion thermodynamics, and substantial volumetric strain effects, which lead to electrochemical failure. This report unlocks a design paradigm of VSe2- x /C in-plane heterojunction with built-in anion vacancy, achieved through an in situ functionalization and self-limited growth approach. Theoretical and experimental investigations reveal the bifunctional role of the Se vacancy in enhancing the ion diffusion kinetics and the structural thermodynamics of Nax VSe2 active phases. Moreover, this in-plane heterostructure facilitates complete face contact between the two components and tight interfacial conductive contact between the conversion phases, resulting in enhanced reaction reversibility. The VSe2- x /C heterojunction electrode exhibits remarkable sodium-ion storage performance, retaining specific capacities of 448.7 and 424.9 mAh g-1 after 1000 cycles at current densities of 5 and 10 A g-1 , respectively. Moreover, it exhibits a high specific capacity of 353.1 mAh g-1 even under the demanding condition of 100 A g-1 , surpassing most previous achievements. The proposed strategy can be extended to other V5 S8- x and V2 O5- x -based heterojunctions, marking a conceptual breakthrough in advanced electrode design for constructing high-performance sodium-ion batteries.

Hydrogen volumetric fraction effects on HCNG refuelling station CAPEX

Greening the transport sector is crucial for the achievement of the ambitious decarbonisation goals set by the Conference of the Parties (COP21) Paris agreement to keep global warming “well below 2 degrees Celsius above preindustrial levels, and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius”. Battery electric vehicles and hydrogen fuel cell electric vehicles will play a key role in the reduction of greenhouse gas emissions in the road mobility. Nonetheless, those technologies still need to face some technological challenges. Hence, hydrogen enriched natural gas (HCNG) can play an important role as bridging technology. This study envisages the upgrade of an existing compressed natural gas (CNG) refuelling station (RS) in HCNG-RS. Particularly, an analysis regarding the impact of different hydrogen volumetric fractions in the blend on the total CAPEX of the HCNG refuelling station is carried out, by evaluating the HCNG fill-up demands for a proper refuelling station sizing. The proposed HCNG refuelling station layout foresee the on-site hydrogen production by means of an electrolyser fed by PV energy. Each component of the station has been adequately sized based on the resulting peak HCNG refuelling demand. The highest CAPEX value is recorded for the 30%vol. HCNG, amounting up to 3.52 M€.

Dynamic modelling of cross-flow printed circuit heat exchangers for multistage reactor intercooling

A reduced-order dynamic model of a cross-flow printed circuit heat exchanger was developed to study both steady-state and transient performance under conditions that would be encountered in multistage catalytic combustion reactors to better understand how they can be used to minimize fluctuations in heat-integrated reactors and intensified processes. Previous transient models for cross-flow heat exchangers rely on an initial steady state and apply only for changes in inlet temperature, but this work presents a model that can be applied to intermediate states or multiple concurrent upstream process changes. Steady-state simulations showed that larger channels reduce volumetric heat transfer performance and effectiveness due to convective resistance. Furthermore, larger channel spacing increases effectiveness but also reduces compactness. Operating temperature was found to have a minimal effect on the overall heat transfer coefficient and effectiveness within the range of conditions studied, and operating pressure was found to have no effect on heat transfer. Transient analyses showed that the response to a unit step in temperature matches closely with an analytical infinite gas velocity model, both for time constants and the overall thermal response, with initial variations in outlet temperatures from ideal-case models below 3.8 % of unit step magnitudes, and average differences below 0.75 %. Transient analyses also show the effects of a finite fluid velocity which is critical in the transient response of large heat exchangers. The presented numerical model can also be more easily extended to complex configurations and can be applied to other changes in inlet conditions such as changing composition and flow rates as are found in combustion applications. A three-fluid thermal management system for a multistage packed-bed microreactor using printed circuit heat exchangers is proposed and modelled to provide a method for temperature regulation and pre-heating of fresh reactor feed.

Effect of Bombyx Mori Silk Fiber Volumetric on Water Sorption of Fiber-reinforced Composite

Background: Dental resin is frequently reinforced with synthetic dental fibers like glass fiber. Dental glass fiber can be challenging to find and costly in Indonesia. Bombyx mori silk fiber is a robust, convenient, and reasonably priced natural fiber substitute. Bombyx mori silk fiber is commonly used in medicinal applications as a post-surgical suture. Aim: The aim of this study was to assess the volumetric effect of Bombyx mori silk fiber on the water sorption of fiber-reinforced composite (FRC). Material and Methods: This study was an experimental laboratory. The materials used in this study were Bombyx mori silk fiber and flowable composite. Four groups of FRC samples were made using volumetric fibers at 0%, 5%, 10%, and 15% (n = 4). The test of water sorption was standardized (ISO 4049). The results were analyzed using one-way ANOVA (p&lt;0.05). Results: The mean of water sorption of Bombyx mori silk fiber FRC for volumetric 0%, 5%, 10%, and 15% were: 0.475±0.030%; 0.681±0.033%; 0.889±0.008%; 1.318±0.039%, respectively. The present study showed that Bombyx mori silk fiber volumetric influenced the water sorption of FRC (p&lt;0.05). Conclusion: The increased Bombyx mori silk fiber volumetric significantly increased the water sorption of FRC. The presence of a small gap caused by the weak interfacial bonds of the dental resin and fiber leads to water penetration.

Stabilities of substitutional solutes in α-iron under uniaxial strain

Nonuniform strain fields in ferritic/martensitic steels working in extreme conditions might induce segregation of alloying solutes. We optimized the structures of iron alloy systems under uniaxial tensile strains along [001] direction within density-functional theory. The calculated segregation energies of solutes Ni, Cu, Al, and Si decrease drastically in a linear fashion as the tensile strain increases up to 17.5%, while those of Co and Ti only change slightly. The segregation energies of solutes V, Nb, Ta, Cr, Mo, and W first decrease and then increase. These results might indicate that, for all solutes studied except Co and Ti, segregation behaviors happen in ferritic/martensitic steels under tensile strains. The shape deformation effect plays a major role in the segregation energies of solutes Cu, Al, Si, Ni, Nb, Ta, Cr, and Mo, while the volumetric effect is dominant for solutes V and W. The segregation energy changes owing to the tensile strain increase from 8% to 14% exhibit a linear relation with the Young modulus changes of the alloys relative to α-iron, which indicates a correlation between the stabilities of solutes and their bonding strength with iron neighbors. The linearly decreasing mixing energies of solutes Mg, Zn and Ga in α-iron with increasing uniaxial strain might suggest a new possible way of fabricating supersaturated iron solid solutions.

Yolk-Shell Gradient-Structured SiOx Anodes Derived from Periodic Mesoporous Organosilicas Enable High-Performance Lithium-Ion Batteries.

Gradient-structured materials hold great promise in the areas of batteries and electrocatalysis. Here, yolk-shell gradient-structured SiOx -based anode (YSG-SiOx /C@C) derived from periodic mesoporous organosilica spheres (PMOs) through a selective etching method is reported. Capitalizing on the poor hydrothermal stability of inorganic silica in organic-inorganic hybrid silica spheres, the inorganic silica component in the hybrid spheres is selectively etched to obtain yolk-shell-structured PMOs. Subsequently, the yolk-shell PMOs are coated with carbon to fabricate YSG-SiOx /C@C. YSG-SiOx /C@C is comprised of a core with uniform distribution of SiOx and carbon at the atomic scale, a middle void layer, and outer layers of SiOx and amorphous carbon. This unique gradient structure and composition from inside to outside not only enhances the electrical conductivity of the SiOx anode and reduces the side reactions, but also reserves void space for the expansion of SiOx , thereby effectively mitigating the stress caused by volumetric effect. As a result, YSG-SiOx /C@C exhibits exceptional cycling stability and rate capability. Specifically, YSG-SiOx /C@C maintains a specific capacity of 627 mAh g-1 after 400 cycles at 0.5 A g-1 , and remains stable even after 550 cycles at current density of 2 A g-1 , achieving a specific capacity of 519 mAh g-1 .

Thermal performance improvement of PCM layers

Thermal shielding through phase change material wallboards exposed to oscillating temperature conditions has been previously studied by several authors. PCM layers provide thermal comfort by releasing(absorbing) latent heat energy, constituting a sort of active cooling(heating) system produced by the dynamics of liquid-solid interfaces. In this work, the effect of volume displacements in the thermal performance of PCM wallboards is analyzed. The thermal energy released(absorbed) at the inner wall is greatly affected by the dynamics of volume displacements and the formation of one or more interfaces, when exposed to temperature oscillations around the melting point of the material. Equations of motion for the thickness of the PCM layer and interfaces, are derived. Volumetric effects produced by the sharp density change of liquid-solid transitions as well as the thermal expansion of each phase are considered in the analysis. We found that the term proportional to the expansion coefficient that appears in the equations of motion is negligible. The effect is hidden by volume displacements produced through the density difference between phases. Semi-analytical methods were used to solve the equations of motion described in this work. We found that the thermal energy released(absorbed) is deeply affected by the initial configuration of phases and the time instant of exposure to ambient conditions. Thermal shielding can be improved through PCM preparation and time of installation, according to the results found in this work. Finally, examples with two alkanes are provided when the external wall is exposed to different weather conditions.