Total Density Research Articles

Relationship between radar reflectivity thresholds and very low frequency/low frequency total lightning for thunderstorm identification

AbstractTo improve our knowledge of the spatio‐temporal correspondence between radar reflectivity and VLF/LF total lightning data, this paper proposes indexes to quantify the horizontal distribution and temporal evolution characteristics between radar composite reflectivity images and total lightning density map, lightning clusters and radar cells with different radar reflectivity thresholds (30, 35, 40, 45 and 50 dBZ), respectively. It is found that the number of radar grid cells with radar reflectivity over 30 dBZ is ten times the number of lightning grid cells. At the identification stage, the lightning activity regions in a radar cell account for less than 30% using thresholds of 30, 35 and 40 dBZ, respectively, and the radar cell has more than one lightning cluster, which means that the mesoscale convective systems typically have more than one draft, and drafts are only small part of the convection. The majority of the centroid deviations is less than 10 km, indicating that there are some shifts between electrically active regions and convective regions. Results suggest that VLF/LF total lightning data are consistent with radar data and total lightning data can be used individually on a smaller spatio‐temporal scale than radar data.

SnO2/CoTeO3 heterojunction for smartly conducting hydrogen evolution linking to organics electrocatalytic oxidation

As a sustainable energy form, hydrogen can be most practically obtained from electrocatalytic water splitting. The familiar organics can be oxidized to more useful intermediates in chemical industries. Herein, a SnO2/(CoTeO3)2 heterojunction is designed as an electrocatalyst for hydrogen evolution reaction (HER) and organic electrocatalytic oxidation. The heterojunction has good electrocatalytic performances with overpotentials of 281 mV at 10 mA cm−2 in 1 M KOH+0.1 M glycerol, 358 mV at 10 mA cm−2 in 1 M KOH +0.33 M urea, 203 mV in 1 M KOH+0.1 M glucose, and 111 mV for HER in 1 M KOH. The glucose is electrocatalytically oxidized to gluconic acid and formic acid. Density functional theory computation shows the formation of the SnO2/(CoTeO3)2 heterojunction makes the total densities of states of SnO2 move to the Fermi level, which is beneficial for adsorption in the electrocatalysis. This work propagandizes a new avenue for heterojunction electrocatalyst is applied for organics oxidation linking to hydrogen production.

The impact of monotherapies for male androgenetic alopecia: A network meta-analysis study.

The evidence base pertaining to the efficacy of monotherapies for androgenetic alopecia (AGA), the most common form of hair loss, is ever expanding-and this warrants a formal comparison therapies' effect on a frequent basis. The objective of the current study was to determine the comparative effect of relevant monotherapies for male AGA. Our aim was achieved by conducting Bayesian network meta-analysis (NMA), under a random effects model, for two outcomes: 6-month change in (1) total and (2) terminal hair density in adult (i.e., aged 18 years and above) men with AGA; these analyses were preceded by a systematic search of the peer-reviewed literature for suitable data. Interventions' surface under the cumulative ranking curve (SUCRA) and pairwise relative effects (quantified as mean differences) were estimated through the NMAs. We determined the comparative effect of 20 active comparators and a control (i.e., placebo/vehicle). "Dutasteride 0.5 mg once daily for 24 weeks" was ranked the most effective in terms of 6-month change in (1) total hair density (SUCRA = 87%) and terminal hair density (SUCRA = 98%). Our results showed that interventions' effectiveness can be dose dependent. Our updated analyses of the up-to-date evidence regarding monotherapies for male AGA showed that the oral form of 5-alpha reductase inhibitors are more effective than oral minoxidil and other newer agents like Botox, microneedling, and photobiomodulation. Our findings can better inform clinical decision making and design of future research studies.

CURLING – I. The influence of point-like image approximation on the outcomes of cluster strong lens modeling

Abstract Cluster-scale strong lensing is a powerful tool for exploring the properties of dark matter and constraining cosmological models. However, due to the complex parameter space, pixelized strong lens modeling in galaxy clusters is computationally expensive, leading to the point-source approximation of strongly lensed extended images, potentially introducing systematic biases. Herein, as the first paper of the ClUsteR strong Lens modelIng for the Next-Generation observations (CURLING) program, we use lensing ray-tracing simulations to quantify the biases and uncertainties arising from the point-like image approximation for JWST-like observations. Our results indicate that the approximation works well for reconstructing the total cluster mass distribution, but can bias the magnification measurements near critical curves and the constraints on the cosmological parameters, the total matter density of the Universe Ωm, and dark energy equation of state parameter w. To mitigate the biases, we propose incorporating the extended surface brightness distribution of lensed sources into the modeling. This approach reduces the bias in magnification from 46.2 per cent to 0.09 per cent for μ ∼ 1000. Furthermore, the median values of cosmological parameters align more closely with the fiducial model. In addition to the improved accuracy, we also demonstrate that the constraining power can be substantially enhanced. In conclusion, it is necessary to model cluster-scale strong lenses with pixelized multiple images, especially for estimating the intrinsic luminosity of highly magnified sources and accurate cosmography in the era of high-precision observations.

Predictors of Metastasis in 68GA-Prostate Specific Membrane Antigen Pet-CT in the Primary Staging of Prostate Cancer

Background: The objective of this study was to investigate factors influencing Gallium 68 Prostate Specific Membrane Antigen Positron Emission Tomography (Ga68 PSMA PET-CT) uptake for primary staging in prostate cancer. Methods: Retrospective analysis was conducted on 499 non-metastatic and 243 de novo metastatic prostate cancer cases undergoing Ga68 PSMA PET-CT. Demographic, clinical, and imaging data were collected and analyzed. Multivariate logistic regression determined independent risk factors for metastasis detection on Ga68 PSMA PET-CT. Results: Metastatic cases showed higher levels of total PSA, PSA density (dPSA) and biopsy ISUP grade group compared to non-metastatic cases. Multivariate analysis identified cT2 stage and dPSA as independent predictors of metastasis detection on Ga68 PSMA PET-CT. Conclusions: Ga68 PSMA PET-CT plays a crucial role in prostate cancer staging, with identified factors such as clinical T stage and dPSA significantly impacting its diagnostic accuracy. These findings underscore the importance of Ga68 PSMA PET-CT in refining clinical staging and guiding treatment decisions for prostate cancer patients.

Constraints on PDS 70 b and c from the dust continuum emission of the circumplanetary discs considering in situ dust evolution

The young T Tauri star PDS 70 has two gas accreting planets sharing one large gap in a pre-transitional disc. Dust continuum emission from PDS 70 c has been detected by Atacama Large Millimeter/submillimeter Array (ALMA) Band 7, considered as the evidence of a circumplanetary disc. However, there has been no detection of the dust emission from the CPD of PDS 70 b. We constrain the planet mass and the gas accretion rate of the planets by introducing a model of dust evolution in the CPDs and reproducing the detection and non-detection of the dust emission. We first develop a 1D steady gas disc model of the CPDs reflecting the planet properties. We then calculate the radial distribution of the dust profiles considering the dust evolution in the gas disc and calculate the total flux density of dust thermal emission from the CPDs. We find positive correlations between the flux density of dust emission and three planet properties, the planet mass, gas accretion rate, and their product called `MMdot'. We then find that the MMdot of PDS 70 c is $ M_ J yr $, corresponding to the planet mass of $ J $ and the gas accretion rate of $ M_ J yr $. This is the first case to succeed in obtaining constraints on planet properties from the flux density of dust continuum emission from a CPD. We also find some loose constraints on the properties of PDS 70 b from the non-detection of its dust emission. We propose possible scenarios for PDS 70 b and c explaining the non-detection respectively detection of the dust emission from their CPDs. The first explanation is that planet c has larger planet mass, larger gas accretion rate, or both than planet b. The other possibility is that the CPD of planet c has a larger amount of dust supply, weaker turbulence, or both than that of planet b. If the dust supply to planet c is larger than b due to its closeness to the outer dust ring, it is also quantitatively consistent with that planet c has weaker Halpha line emission than planet b considering the dust extinction effect.

Pressure Effects on the Structural, Electronic, Elastic, Optical, and Vibrational Properties of YMg Intermetallic Compounds:A First-Principles Study

Abstract The properties of YMg in B2 structure have been comprehensively analysed using the first-principles plane-wave pseudopotential method. Specifically, the structural, electronic, elastic, vibrational, and optical properties were investigated using the generalized gradient approximation (GGA) method in the context of density functional theory. The Vienna ab initio simulation package (VASP) was utilized for these calculations. The computed lattice parameter (3.803 Å) and bulk modulus (41.33 GPa) are consistent with the earlier data on ambient pressure. The electronic band structure and energy-dependent density of states reveal the metallic nature of the titled compounds. The Born stability requirements confirmed the mechanical stability. The analysis of Pugh's and Poisson's ratios and Cauchy's pressure reveals that YMg is ductile under the pressures in consideration. According to several anisotropy indices, the compound is noticeably anisotropic both in ambient and under pressure. Our investigation includes an analysis of several fundamental mechanical parameters of the material, including the bulk modulus, the pressure derivative of the Zener anisotropy factor, Poisson's ratio, isotropic shear modulus and Young's modulus with a particular focus on their dependence on pressure. We have determined that the elastic constants obtained remain mechanically stable, satisfying the Born Stability conditions even at high pressures of up to 60 GPa. To explore the dynamic stability of YMg, we analysed the material's phonon dispersion curves. The examined compound displays stability under dynamic conditions from 0 GPa to 30 GPa, as evidenced by its positive vibration frequencies. However, this stability is not sustained under higher pressure, as the compound becomes unstable after 30 GPa to 70 GPa. 
The electronic band structure and density of states diagrams demonstrate YMg's metallic properties. At atmospheric pressure (0 GPa), the total density of states (TDOS) near the Fermi level is approximately 1.63 states/eV, with pressure application reducing DOS. The dielectric function, refractive index, and energy loss spectra are examined within the 0–20 eV energy range. YMg exhibits its highest absorption between 4 and 11 eV. The peak optical conductivity is observed around 0.78 eV (equivalent to 1589.5409 nm), while the most significant energy loss occurs at 11.90 eV, roughly corresponding to 2.8 Hz in the ultraviolet spectrum. Moreover, we extensively analyzed the material's phonon thermodynamic and optical properties, providing insights into its behavior under various conditions. The outcomes acquired at zero pressure are generally coherent with the current theoretical values.

Copepod distribution and diversity in the coastal areas of Ban-ao and Lambajon, Davao Oriental, Philippines: Environmental influences and conservation implications

Copepods are essential components of marine ecosystems, facilitating energy transfer within these complex systems. The study investigates copepod diversity and distribution in Ban-ao and Lambajon coastal areas in Baganga, Davao Oriental, highlighting the environmental factors influencing copepod populations. Four copepod families representing different orders were identified, with Harpacticoida, Calanoida, and Cyclopoida prevalent in both sites, while Misophrioida was exclusive to Lambajon. Physico-chemical parameters such as dissolved oxygen (DO), pH, salinity, sediment composition, water depth, and temperature were analyzed to understand their correlation with copepod density. The study reveals variations in copepod density and abundance between the sites, with Lambajon showing a higher total density (49 ind/cm³) compared to Ban-ao (35 ind/cm³). The Pearson correlation matrix illustrates complex relationships between copepod density and environmental parameters in each site. In Ban-ao, strong positive correlations were found between copepod density and DO (r = 0.65) and temperature (r = 0.36). In Lambajon, positive correlations existed between water depth and copepod density (r = 0.20). Both sites exhibit low copepod diversity overall, potentially due to anthropogenic pressures. These findings emphasize the need for further research to understand the interactions between environmental factors and copepod diversity, essential for effective conservation and management strategies in these coastal ecosystems.

Changes in thoracic radio density after living donor liver transplantation.

The outcomes after liver transplantation have greatly improved, which has resulted in greater focus on improving non-hepatic outcomes of liver transplantation. The present study aimed to evaluate thoracic spine radio density in children and adolescents after liver transplantation. A total of 116 patients who underwent living donor liver transplantation were retrospectively analyzed. The radio density at the eleventh thoracic vertebra was measured using computed tomography scan performed preoperatively then annually for 5 years postoperatively and subsequently every 2 or 3 years. The mean thoracic radio density of male recipients of male grafts had the lowest values during the study. The radio density of patients receiving a graft from a female donor was higher than in recipients with grafts from males. Total mean radio density decreased for first 5 years postoperatively and then increased. Changes in radio density were equally distributed in both steroid withdrawal and no steroid withdrawal groups for 5 years, after which patients with steroid withdrawal had a greater increase. Changes in radio density were equally distributed in both the steroid withdrawal and no steroid withdrawal groups up to age 20, after which patients in the steroid withdrawal group had a greater increase. Gender differences may affect the outcome of radio density changes after transplantation. Given the moderate association between thoracic radio density and bone mineral density in skeletally mature adults and further studies are needed to validate this relationship between thoracic radio density and bone mineral density changes in pediatric liver transplantation.

Cross-sectional associations between accelerometer-measured physical activity and hip bone mineral density. The Tromsø study 2015–2016

Cross-sectional associations between accelerometer-measured physical activity and hip bone mineral density. The Tromsø study 2015–2016

Growth and productivity of maize (Zea mays) as influenced by sequential and combined application of tank mix herbicides

The experiment was conducted during 2021–22 at Govind Ballabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand to evaluate the impact of sequential and tank mix application of pre- and post-emergence herbicide on weed dynamics and maize productivity. The study was comprised of 9 treatments viz. Weedy (T1 ); Weed free (T2 ); Pre-emergence (PE) application of Atrazine -1 kg a.i./ha fb hand weeding (T3 ); PE application of Atrazine - 0.75 kg a.i./ha fb Post Emergence (Post E) application of Topramezone - 25.2 g a.i./ha (T4 ); PE application of Atrazine - 0.75 kg a.i./ha fb Post E application of Tembotrione - 120 g a.i./ha (T5 ); PE application of Atrazine - 1.0 kg a.i./ha fb Post E application of Topramezone - 25.2 g a.i./ha (T6 ); PE application of Atrazine - 1.0 kg a.i./ha fb Post E application of Tembotrione - 120 g a.i./ha (T7 ); Early Post E application of Topramezone - 25.2 g a.i./ha + Atrazine - 0.75 kg a.i./ha (T8 ) and Early Post E application of Tembotrione - 120 g a.i./ha + Atrazine - 0.75 kg a.i./ha (T9 ). Eleusine indica, Echinochloa colona, Digitaria sanguinalis and Eragrostis japonica were dominant among grassy weeds whereas broad leaf weeds included Cucumis melo, Phyllanthus niruri, Cleome viscosa and Commelina benghalensis. Cyperus rotundus was dominant among sedges. Topramezone - 25.2 g a.i./ha + Atrazine - 0.75 kg a.i./ha Early Post E resulted significantly lower total weed density and was similar to other herbicidal treatments. The highest grain yield (7.2 t/ha) was recorded in a weed-free crop that was similar to all herbicidetreated crops and significantly higher than the weedy crop. Tank mix application of atrazine - 0.75 kg a.i./ha with tembotrione 120 g a.i./ha or topramezone 25.2 g a.i./ha at 15 DAS can be suggested owing to higher grain yield and profits for farmers while lowering the dose and expenses involved in manual weeding and spraying atrazine separately.

Brown manuring for improved crop growth, yield and energetics of wet seeded-rice (Oryza sativa) in the coastal deltaic eco-system

A field experiment was conducted during October 2020–January 2021 at Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal, Puducherry to study the effect of different seeding rates of [Sesbania bispinosa (Jacq.) W. Wight] (Sesbania) in rice co-culture along with suitable post-emergence herbicides for brown manuring on crop productivity and energetics in wet seeded rice (Oryza sativa L.). The experiment consisted of 10 treatments, viz. T1 ,Sesbania seeding rate for brown manuring (BM) @15 kg/ha with 2,4-D 0.5 kg/ha; T2 , Sesbania seeding rate for BM @20 kg/ha with 2,4-D 0.5 kg/ha; T3 , Sesbania seeding rate for BM @25 kg/ha with 2,4-D 0.5 kg/ha; T4 , Sesbania seeding rate for BM @15 kg/ha with bispyribac sodium 25 g/ha; T5 , Sesbania seeding rate for BM @20 kg/ha with bispyribac sodium 25 g/ha; T6 , Sesbania seeding rate for BM @25 kg/ha with bispyribac sodium 25 g/ha; T7 , rice alone with 2,4-D 0.5 kg/ha; T8 , rice alone with bispyribac sodium 25 g/ha; T9 , hand weeding twice at 20 and 40 DAS (days after sowing); T10, unweeded control in a randomized block design (RBD) with three replications. Sesbania seeding rate for brown manuring (BM) @25 kg/ha + 2,4-D 0.5 kg/ha recorded significantly lower total weed density (73.3 no./m2) and weed dry weight (37.0 g/m2). Significantly higher crop growth rate (CGR) (528.2 g/m2 /day), plant height (132.8 cm) and rice yield (4823 kg/ha) were observed under Sesbania seeding rate for BM @25 kg/ha + 2,4-D 0.5 kg/ha which was comparable with Sesbania seeding rate for BM @25 kg/ha + bispyribac sodium 25 g/ha but superior to treatments without BM and eventually resulted in higher energy productivity (0.59 to 0.60 kg/MJ), energy profitability (7.74 to 7.77 kg/MJ) and the energy use efficiency (8.74 to 8.77). Thus, Sesbania seeding rate @25 kg/ha along with spraying either 2,4-D 0.5 kg/ha or bispyribac sodium 25 g/ha for brown manuring could be recommended in wet seeded rice.

Strain energy density and entire fracture surface parameters relationship for LCF life prediction of additively manufactured 18Ni300 steel

In this study, the connection between total strain energy density and fracture surface topography is investigated in additively manufactured maraging steel exposed to low-cycle fatigue loading. The specimens were fabricated using laser beam powder bed fusion (LB-PBF) and examined under fully-reversed strain-controlled setup at strain amplitudes scale from 0.3% to 1.0%. The post-mortem fracture surfaces were explored using a non-contact 3D surface topography measuring system and the entire fracture surface method. The focus is on the relationship between fatigue characteristics, expressed by the total strain energy density, and the fracture surface topography features, represented by areal, volume, and fractal dimension factors. A fatigue life prediction model based on total strain energy density and fracture surface topography parameters is proposed. The presented model shows good accordance with fatigue test results and outperforms other existing models based on the strain energy density. This model can be useful for post-failure analysis of engineering elements under low-cycle fatigue, especially for materials produced by additive manufacturing (AM).

Urban trees' potential for regulatory services in the urban environment: an exploration of carbon sequestration.

Urbanisation has emerged as a formidable challenge for urban policymakers, reaching unparalleled heights and unsettling the ecological equilibrium of the cities. Urban areas now grapple with many issues encompassing climate change, resource depletion, population surges and increased pollution levels. Many planned cities have planted trees and other vegetation within the urban sectors to enhance air quality, mitigate climate effects and provide valuable ecosystem services. This study assessed tree species diversity and their potential for carbon sequestration in Panjab University Campus, Chandigarh. We established 188 plots, each comprising randomly selected quadrats measuring 10 m × 10 m, encompassing areas with varying levels of vegetation, ranging from low to moderate and high density. We used four different allometric equations to estimate tree biomass and carbon stock. Our findings revealed that 92 tree species belong to 72 genera and 35 families, with a total tree density of 975 ha-1. The total CO2 sequestration in form of carbon stock was 18,769.46 Mg C ha-1, with Manilkara hexandra (1239.20 Mg C ha-1), Ficus benghalensis (1072.24 Mg C ha-1), Kigelia pinnata (989.89 Mg C ha-1) and Lagerstroemia floribunda (716.88 Mg C ha-1) being the top contributors. Specifically, the equation of Chave et al. (2005) without tree height yielded the highest biomass and carbon stock estimates than other equations. The present study underscores the vital role of trees on the campus as potent carbon reservoirs meet to maintain an aesthetic sense for biotic components and alleviate rising levels of CO2 in the atmospheric environment. By emphasising the role of urban trees as potent carbon reservoirs, the study underscores the importance of integrating green infrastructure into urban planning strategies. Furthermore, it offers valuable guidance for urban planners. It suggests that strategic tree planting and maintenance can enhance green spaces, regulate temperatures and ultimately support regional and global climate change mitigation goals. Incorporating these findings into urban planning processes can aid policymakers in developing resilient, ecologically sustainable cities worldwide.

The influence of trinucleotide repeats in the androgen receptor gene on androgen-related traits and diseases.

Trinucleotide repeats in the androgen receptor have been proposed to influence testosterone signaling in men, but the clinical relevance of these trinucleotide repeats remains controversial. To examine how androgen receptor trinucleotide repeat lengths affect androgen-related traits and disease risks and whether they influence the clinical importance of circulating testosterone levels. We quantified CAG and GGC repeat lengths in the androgen receptor (AR) gene of European-ancestry male participants in UK Biobank from whole-genome and whole-exome sequence data using ExpansionHunter, and tested associations with androgen-related traits and diseases. We also examined whether the associations between testosterone levels and these outcomes were affected by adjustment for the repeat lengths. We successfully quantified the repeat lengths from whole-genome and/or whole-exome sequence data in 181,217 males. Both repeat lengths were shown to be positively associated with circulating total testosterone level and bone mineral density, whereas CAG repeat length was negatively associated with male-pattern baldness, but their effects were relatively small and were not associated with most of the other outcomes. Circulating total testosterone level was associated with various outcomes, but this relationship was not affected by adjustment for the repeat lengths. In this large-scale study, we found that longer CAG and GGC repeats in the AR gene influence androgen resistance, elevate circulating testosterone level via a feedback loop and play a role in some androgen-targeted tissues. Generally, however, circulating testosterone level is a more important determinant of androgen action in males than repeat lengths.

Coherence measurements of polaritons in thermal equilibrium reveal a power law for two-dimensional condensates.

We have created a spatially homogeneous polariton condensate in thermal equilibrium, up to very high condensate fraction. Under these conditions, we have measured the coherence as a function of momentum and determined the total coherent fraction of this boson system from very low density up to density well above the condensation transition. These measurements reveal a consistent power law for the coherent fraction as a function of the total density over nearly three orders of its magnitude. The same power law is seen in numerical simulations solving the two-dimensional Gross-Pitaevskii equation for the equilibrium coherence.

First-principles screening of XSbF3 (X = Ba and Ra) fluoroperovskites: An insight into structural, optoelectronic and thermal properties

Abstract This work presents a computational study of the physical properties such as structural, electronic, optical and thermal properties of XSbF3 (X = Ba and Ra) fluoroperovskites. The calculations were performed using the density functional theory (DFT) calculations in conjunction with Quantum Espresso code. The stability of the crystal structure XSbF3 compounds is determined by binding energy 〖(E〗_b) computations. The E_b values for BaSbF3 and RaSbF3 compounds are -19.25 and -20.04 eV respectively, indicating that both studied compounds are stable. The optimized lattice constants for BaSbF3 and RaSbF3 compounds are 5.03 and 5.06 Å, respectively. The evaluation of electronic properties is conducted by electronic band structure, total density of states (DOS), and partial density of states (PDOS). It is observed from the PDOS plots that the p-states of Sb and F whereas the d-states of X atoms have the major contribution in the formation of the band structure. Various optical properties have been computed and compared. The static value of ε_1 (0) highlights the metallic nature of the studied compounds while RaSbF3 stands out for having the highest recorded value of ε_2 (0). The maximum n(ω) values for BaSbF3 and RaSbF3 are 8.46 and 6.86 respectively indicating their potential for photoelectric applications. Furthermore when examining the properties it is evident that the BaSbF3 compound stands out as a material for energy storage because of its higher electron energy at 2.36 KJ/N.mol and lower electron free energy of -2.55 KJ/N.mol compared to the RaSbF3 compound. On the other hand, the RaSbF3 compound is an efficient material for catalysis due to its high ability to absorb heat energy from the external source, as compared to the BaSbF3 compound. This study is the first computational investigation of XSbF3 (X is Ba and Ra) compounds, which provides valuable insights into the physical properties of sb-based fluroperovskites and their potential applications.

Strain effects on electronic and dynamical properties of half-Heusler semiconductors: insights from Meta-GGA

Abstract In this study, we investigated the effects of mechanical strain, including both tensile and compressive strains, on the electronic properties and dynamical stability of two ternary half-Heusler compounds: TiIrSb and ZrIrSb. We employed the plan wave pseudo-potential method (PW-PP) within the density functional theory (DFT) framework. Our calculations were performed using both the GGA-PBE and Meta-GGA-SCAN approximations. Furthermore, to compute the phonon dispersion, we employed the R2SCAN functional instead of SCAN for both compounds, addressing numerical challenges encountered with the latter.

In the absence of strain, our calculations revealed that both compounds exhibit semiconducting behavior, featuring an indirect band gap at identical locations in the Brillouin Zone. Notably, the SCAN functional consistently predicted a larger band gap compared to the corresponding values obtained with PBE for both compounds. Specifically, the band gap expanded significantly, creating a noticeable separation between the valence and conduction bands. For TiIrSb, it increased from 0.84 eV with PBE to 1.05 eV with SCAN, while for ZrIrSb, it increased from 1.41 eV with PBE to 1.71 eV with SCAN. Under the application of strains, both compounds demonstrated an increased band gap under compressive strain, while the application of tensile strain led to a decrease in the band gap, resulting in an indirect-to-direct band gap transition for ZrIrSb. Remarkably, under all strain values, whether tensile or compressive, the SCAN functional consistently exhibited a larger band gap compared to PBE, indicating its accurate description of the material's electronic structure. The calculated Density of States (DOS) and Partial Density of States (PDOS) reveal that the valence band extremum (VBM) primarily consisted of Ti/Zr-d orbitals, while the conduction band maxima (CBM) predominantly involved strong hybridization between Ti/Zr-d, Ir-d, and Sb-p states. Notably, the SCAN functional predicted higher orbital contributions to Total Density of States (TDOS) compared to the PBE approximation. Importantly, both half-Heusler materials exhibited mechanical and dynamical stability under various strain condition

How Are Microstructural Defect Interactions Linked to Simultaneous Intergranular and Transgranular Fracture Modes in Polycrystalline Systems?

The major objective of this investigation is to fundamentally understand and predict how intergranular (IG) and transgranular (TG) fracture modes nucleate and propagate in f.c.c. polycrystalline systems due to defects, such as total and partial dislocation densities and grain boundary (GB) structures and misorientations. A dislocation density crystalline plasticity (DCP) formulation based on the evolution and interaction of total and partial dislocation densities was integrated with a recently developed fracture approach to investigate the fracture nucleation and propagation of simultaneous multiple fracture events, including both IG and TG fracture events. The aggregate grains and GB orientations and morphologies are based on EBSD measurements that are representative of polycrystalline copper aggregates with a broad range of random high angle and low angle GBs. The predictions indicate that dislocation density pileups induce IG fracture due to interrelated stress, slip, and total and partial dislocation density accumulations and interactions for both high angle GBs (HAGBs) and low angle GBs (LAGBs). TG fracture nucleation and propagation occurred due to normal stress accumulations, which exceeds the fracture stress, along cleavage planes. Furthermore, it is shown how IG cracks transition from the GB plane to the cleavage planes as cracks nucleate and propagate. Accumulated plastic zones due to different slip system activities can impede and blunt crack propagation and fronts. These plastic zones form due to high Lomer and Shockley partial dislocation densities. These predictions, which are consistent with experimental observations, provide a fundamental understanding of how simultaneous failure modes initiate and propagate for physically representative microstructures.

Temperature stratification in a molecular shock: Analysis of the emission of H2 pure rotational lines in IC443G

Context. Supernovae remnants (SNRs) represent a major source of feedback from stars on the interstellar medium of galaxies. During the latest stage of supernova explosions (which lasts 10–100 kyr), shock waves produced by the initial blast modify the chemistry of gas and dust, inject kinetic energy in the surroundings, and may alter star formation characteristics. Simultaneously, γ-ray emission is generated by the interaction between the ambient medium and cosmic rays, in particular those locally accelerated in the early stages of the explosion. Aims. We aim to estimate the total molecular mass, local density, and total column density of H2 and the temperature structure in a shocked clump interacting with the supernova remnant IC443 located in a region where cosmic rays interact with the interstellar medium. Measuring the mass of the dense and neutral component of the medium is a prerequisite to understanding the chemistry, energetics, and GeV to TeV γ-ray emission. Methods. Assuming that the emission of H2 pure rotational lines is produced by a collection of gas layers with variable temperature, we compared Spitzer/IRS emission maps for the ν = 0–0 S(0) to S(7) lines with a thermal admixture model. Our description is based on a power-law distribution of thermalized components with temperatures varying between Tmin = 25 K and Tmax = 1500 K. Results. Our thermal admixture model allows the level populations of H2 to be described by a power-law distribution dN = ΛT−ΓdT, with Γ ~ 2.2−4.7. We measured a total mass MH2 = 220−80+110 M⊙ across the Spitzer/IRS field of observations. Conclusions. Our analysis shows that an estimate of the cold molecular gas temperature is paramount to accurately constraining the H2 mass, although the mass remains affected by significant uncertainties due to the assumptions on the gas temperature distribution.