Temperature-dependent Mass Research Articles

LES investigations of turbulent heat transfer structures with exponential power escalation

The BORAX-type accident is a key scenario in the safety design of pool-type experimental nuclear reactors. It considers a reactivity insertion large enough to initiate an exponential power escalation with a period as small as tens of milliseconds, necessitating effective heat removal by the coolant system. This study presents a computational analysis of single-phase transient heat transfer under thermal-hydraulic conditions relevant to such reactors, focusing on turbulent channel flow between planar fuel plates with highly subcooled water. Our investigation uses Large Eddy Simulation (LES) performed with TrioCFD, the open-source CFD code developed by the French Atomic Energy Commission (CEA). Several modeling options are tested: incompressible flow with temperature as a passive scalar, incompressible flow with varying viscosity, and quasicompressible flow with temperature-dependent viscosity and mass density. To evaluate the accuracy of our physical models, all simulations were performed under uniform conditions, using the same experimental parameters, mesh, and numerical strategies. The specific examined scenario involves a highly subcooled turbulent channel flow at moderate pressure, experiencing an exponential power increase. We ensure detailed turbulence resolution at the Batchelor scale in the wall normal direction close to the heating wall. This communication presents a comparative study of LES simulations of the single-phase flow under exponential power excursion at the wall. Subsequent analyses focused on the impact of different velocity-temperature couplings on the prediction of wall heat transfer, incorporating comparisons with experimental infrared thermometry measurements. Early in the transient phase, temperature peaks are confined within turbulent streaks, as reported in the existing literature. However, as the exponential power transient unfolds, the viscous layer and streak structures destabilize, leading to a more dispersed distribution of hot spots. Preliminary findings suggest a transition in heat transfer modes from turbulence-driven to conduction during the final stages of the single-phase transient.

Identification of the Thermal Activation Network in Human 15-Lipoxygenase-2: Divergence from Plant Orthologs and Its Relationship to Hydrogen Tunneling Activation Barriers.

The oxidation of polyunsaturated fatty acids by lipoxygenases (LOXs) is initiated by a C-H cleavage step in which the hydrogen atom is transferred quantum mechanically (i.e., via tunneling). In these reactions, protein thermal motions facilitate the conversion of ground-state enzyme-substrate complexes to tunneling-ready configurations and are thus important for transferring energy from the solvent to the active site for the activation of catalysis. In this report, we employed temperature-dependent hydrogen-deuterium exchange mass spectrometry (TDHDX-MS) to identify catalytically linked, thermally activated peptides in a representative animal LOX, human epithelial 15-LOX-2. TDHDX-MS of wild-type 15-LOX-2 was compared to two active site mutations that retain structural stability but have increased activation energies (Ea) of catalysis. The Ea value of one variant, V427L, is implicated to arise from suboptimal substrate positioning by increased active-site side chain rotamer dynamics, as determined by X-ray crystallography and ensemble refinement. The resolved thermal network from the comparative Eas of TDHDX-MS between wild-type and V426A is localized along the front face of the 15-LOX-2 catalytic domain. The network contains a clustering of isoleucine, leucine, and valine side chains within the helical peptides. This thermal network of 15-LOX-2 is different in location, area, and backbone structure compared to a model plant lipoxygenase from soybean that exhibits a low Ea value of catalysis compared to the human ortholog. The presented data provide insights into the divergence of thermally activated protein motions in plant and animal LOXs and their relationships to the enthalpic barriers for facilitating hydrogen tunneling.

Analysis of heat and mass transfer of a non-linear convective heat generating fluid flow in a porous medium with variable viscosity

The present study addresses the significance of analyzing the heat and mass transfer characteristics of a non-linear convective fluid flow featuring variable viscosity within a porous medium. Our focus lies on understanding the impact of varying viscosity on the hydromagnetic coupling stress, particularly in the presence of internal heat generation. The fluid is confined within a porous medium, and convection cooling takes place at both wall of the fluid. A key assumption in our investigation is the nonlinearity nature of the buoyancy force, specifically when there is a substantial difference in temperature and concentration within the fluid and its surroundings, the buoyancy force becomes quadratic. The exploration of couple stress fluids, alongside considerations of temperature-dependent internal heat generation and mass transfer, contributes to advancing our understanding of thermal system performance. By accounting for nonlinearity in density, temperature, and concentration, the research aims to provide more accurate results than previous linear models, crucial for optimizing energy consumption in practical applications such as nuclear reactors and heat exchangers. Dealing with this type of problem often pose significant challenges, as they often lack analytical solutions, necessitating the use of more advanced numerical methods or approximation techniques. We employ Spectral Quasilinearisation Method (SQLM) to solve the coupled non-linear boundary value problems (PDE) arising from the model, momentum equation, energy equation, concentration equation, and entropy generation. The obtained results are then validated using the Runge–Kutta method and a good agreement is achieved. The findings for the dimensionless velocity, temperature, mass concentration and entropy generation are presented in graphics and in table manner, and effects of controlling parameters are extensively explained. The results highlight that an increase in variable viscosity leads to an enhancement in the velocity profile, while simultaneously reducing the temperature in the system. Furthermore, increments in the non-linear convection parameter and coupling stress parameter result in an appreciation of the velocity profile, temperature profile, and entropy generation rate.

Revealing Molecular-Scale Structural Changes in Polymer Nanocomposites during Thermo-Oxidative Degradation Using Evolved Gas Analysis with High-Resolution Time-of-Flight Mass Spectrometry Combined with Principal Component Analysis and Kendrick Mass Defect Analysis.

This study introduces a novel method that utilizes evolved gas analysis with time-of-flight mass spectrometry (EGA-TOFMS) coupled with principal component analysis (PCA) and Kendrick mass defect (KMD) analysis, called EGA-PCA-KMD, to analyze complex structural changes in polymer materials during thermo-oxidative degradation. While EGA-TOFMS captures exact mass data related to the degradation components in the temperature-dependent mass spectra of the evolved products, numerous high-resolution mass spectra with large amounts of ion signals and varying intensities provide challenges for interpretation. To address this, we employed mathematical decomposition through PCA to selectively extract information about the ion series specific to the products that evolved from the degradation components. Additionally, KMD analysis was applied to the attribution of the exact mass signals extracted from the PCA, which categorizes and visualizes depending on the molecular compositions in a two-dimensional plot. The complex structural changes of the triblock copolymer thermoplastic elastomer and its nanocomposites containing nanodiamonds during thermo-oxidative degradation were elucidated using EGA-PCA-KMD to demonstrate the effectiveness of this characterization technique for polymer degradation. Furthermore, it is revealed that the formation of rigid matrix-filler interfacial interaction via the π-π stacking and chemical bonds in the nanocomposites contributes to improvement in the stability toward thermo-oxidative degradation. Our results highlight the benefits of EGA-PCA-KMD and provide valuable insights into polymer degradation.

The Effect of Pre-washing Process with NaOH Solution on the Surface Area in Activated Carbon Production

The alkaline pre-washing process in the production of activated carbon is an important step and a factor that affects the characteristics of activated carbon. Alkaline pre-washing is used to optimize the surface properties of activated carbon, increase its adsorption capacity, and remove unwanted substances.
 
 In this study, hazelnut shells were selected as the raw material for producing activated carbon. ZnCl2 was used for chemical activation, and physical activation was carried out at 650 °C. However, prior to the chemical activation process, a pre-washing process with NaOH solution was applied to remove acidic groups present in the raw material. The structural properties of the activated carbon obtained from samples subjected to the pre-washing process and those without the pre-washing process were determined using Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) for surface morphology, Brunauer-Emmet-Teller (BET) for pore size analysis, and Thermogravimetric Analysis (TGA) for temperature-dependent mass loss.
 
 The surface area of the activated carbon produced without pre-washing with NaOH solution was found to be 770 m²/g, with a carbon content of 87.10% by weight. After the pre-washing process with NaOH solution and subsequent chemical and physical activation, the surface area of the activated carbon increased to 1935 m²/g, with a carbon content of 95.51% by weight. Therefore, subjecting the raw material to the pre-washing process with NaOH solution not only increased the carbon content but also increased the surface area value by approximately 2.5 times.

Asteroseismic Study of KUV03442+0719 with Parallax Constraints

Hydrogen atmosphere white dwarf KUV03442+0719 was first reported as a pulsator by Gianninas et al. in 2006. Follow-up campaigns by Su et al. revealed more periods. Some spectroscopic results suggest that KUV03442+0719 has a slightly below-average mass and an effective temperature of 11,000 K. However, Gaia data (parallax and magnitude) suggest that it may be a low-mass white dwarf. Such an object would have a helium core. We perform asteroseismic fitting of KUV03442+0719, modeling it both as a carbon/oxygen normal mass white dwarf, and a helium-core low-mass white dwarf. To perform the study, we perform a grid search with WDEC models, refined by simplex minimization of the best fits. Both analyses result in best-fit models that are comparable in terms of quality of fit. More pulsation data would be required to allow us to distinguish between the two scenarios. We present and contrast our results with expectations from stellar evolution. We also provide analytic formulae for a temperature-dependent mass–radius relationship for helium-core white dwarfs.

Multi-physical analysis of ablation for C/C composites based on peridynamics

C/C composite material is one of the most widely used thermal protection materials for hypersonic vehicles. As coupled with fluid dynamics, chemical reaction, heat transfer and ablation recession, its numerical simulation is challenging and complicated. In this study, a multi-physical analysis approach for the stripping process during ablation based on peridynamics is proposed. Aerodynamic parameters and heat flux distribution are determined by empirical formulas. The energy balance on the ablative wall has been taken into account for the thermal boundary conditions and the temperature field is obtained by using bond-based peridynamics. Then, the temperature-dependent dimensionless mass flux and surface recession rate are evaluated by solving the equations involving mass conservation of surface elements and chemical equilibrium of reactions. Meanwhile, considering the breaking of bonds and the deletion of material points in this model, the phenomenon of ablation and stripping process of material on the surface can be simulated. A C/C one-dimensional model is built to verify the effectiveness of the methodology, and the peridynamic results agree with the experimental observation from literatures well. Finally, after combining fluid dynamics, chemical reaction, heat transfer and ablation recession, the exterior shape and temperature field at a nose tip of a hypersonic vehicle are predicted.

Effects of ZSM-5 zeolite on pyrolysis of polystyrene: from stabilizing to catalyzing.

Nonisothermal pyrolysis measurements of polystyrene (PS)/ZSM-5 zeolite hybrids are conducted in N2 and thermogravimetric results have been kinetically analyzed with different isoconversional methods. Experimental results show that the addition of 5 and 10 wt.% ZSM-5 zeolite has increased the initial pyrolysis temperature of PS while the addition of 20 and 30 wt.% ZSM-5 zeolite can significantly decrease the initial pyrolysis temperature of PS. Elevated activation energy is resulted by adding low zeolite amount whereas reduced activation energy is obtained by adding high ZSM-5 amounts. The effect of zeolite ZSM-5 on PS pyrolysis can thus be observed to transfer from stabilizing to catalyzing. Furthermore, the pyrolysis mechanism functions of PS/zeolite hybrids are determined by integrating the master plots method with a new compensation effect method, and the most appropriate reaction models are found to be F0.92, F0.85, F0.56 and A1.32 for describing the pyrolysis of the PS/ZSM-5 hybrids with a zeolite loading of 5, 10, 20 and 30 wt.%, respectively. With the kinetic parameters thus available, the temperature-dependent mass conversion curves have been recast, leading to satisfactory simulations for PS/ZSM-5 hybrids.

A Value-added COSMOS2020 Catalog of Physical Properties: Constraining Temperature-dependent Initial Mass Function

This work presents and releases a catalog of new photometrically derived physical properties for the ∼105 most well-measured galaxies in the COSMOS field on the sky. Using a recently developed technique, spectral energy distributions are modeled assuming a stellar initial mass function (IMF) that depends on the temperature of gas in star-forming regions. The method is applied to the largest current sample of high-quality panchromatic photometry, the COSMOS2020 catalog, that allows for testing this assumption. It is found that the galaxies exhibit a continuum of IMF and gas temperatures, most of which are bottom-lighter than measured in the Milky Way. As a consequence, the stellar masses and star formation rates of most galaxies here are found to be lower than those measured by traditional techniques in the COSMOS2020 catalog by factors of ∼1.6–3.5 and 2.5–70.0, respectively, with the change being the strongest for the most active galaxies. The resulting physical properties provide new insights into variation of the IMF-derived gas temperature along the star-forming main sequence and at quiescence, produce a sharp and coherent picture of downsizing, as seen from the stellar mass functions, and hint at a possible high-temperature and high-density stage of early galactic evolution.

BET and Kelvin Analyses by Thermogravimetric Desorption.

Porous solids with nanometer-sized pores and large surface areas are a highly important class of materials. Uses of such materials include filtration, batteries, catalysts, and carbon sequestration. These porous solids are characterized by their surface areas, typically >100 m2/g, and pore size distributions. These parameters are typically measured using cryogenic physisorption, frequently referred to as Brunauer-Emmett-Teller (BET) analysis when BET theory is applied to interpret experimental results. Cryogenic physisorption and related analysis elucidate how a particular solid interacts with the cryogenic adsorbate, but this can be a poor predictor of how that solid will interact with other adsorbates, limiting the applicability of the results. Additionally, the cryogenic temperatures and deep vacuum required for cryogenic physisorption can cause kinetic limitations and experimental difficulties. This method nevertheless remains the standard technique to characterize porous materials for a wide variety of applications due to limited other options. In this work, a thermogravimetric desorption technique for determining surface areas and pore size distributions of porous solids available to adsorbates having boiling points above ambient temperature at ambient pressure is presented. A thermogravimetric analyzer (TGA) is used to measure temperature-dependent adsorbate mass loss, and isotherms are derived. For systems that exhibit multilayer formation, BET theory is applied to isotherms to derive specific surface areas. For systems that do not exhibit multilayer formation, the Kelvin equation is applied to determine pore size distributions and surface areas for the porous materials. In this study, the thermogravimetric method is applied to four adsorbents and two adsorbates─water and toluene─and results are compared to cryogenic physisorption results.

Transient Nonlinear Heat Conduction in Concrete Structures: A Semi-Analytical Approach.

Thermal loading, especially in fire scenarios, challenges the safety and long-term durability of concrete structures. The resulting heat propagation within the structure is governed by the heat conduction equation, which can be difficult to solve analytically because of the nonlinearity related to the thermophysical properties of concrete. A semi-analytical approach for the transient nonlinear heat conduction problem in concrete structures was established in the present work. The nonlinearity related to the temperature-dependent thermal conductivity, mass density, and specific heat capacity of heated concrete was taken into consideration. A Taylor series approximate solution was first established within a small neighborhood, employing the Boltzmann transformation in combination with the mean value theorem. Thereafter, it was extended to the whole domain by utilizing the Bernstein polynomial. The semi-analytical approach was validated by comparing it with the numerical results of two independent Finite Element simulations of nonlinear heat conduction along concrete plates, subjected to either moderate or fierce thermal loading. Absolute values of the relative errors are smaller than 5%. The validated semi-analytical approach was further applied to prediction of the temporal evolution of the temperature field of a scaled model of a subway station, subjected to fire disaster. The nonlinearities, related to the time-dependent surface temperature and the temperature-dependent thermophysical properties of concrete, were taken into consideration. The predictions agree well with the experimental measurements. The established semi-analytical approach exhibits good accuracy and stability, providing insight into the interaction between the thermophysical properties of concrete in the heat conduction process.

Temperature-dependent particle mass emission rate during heating of edible oils and their regression models

Particulate matter emitted by heated cooking oil is hazardous to human health. To develop effective mitigation strategies, it is critical to know the amount of the emitted particles. The purpose of this research is to estimate the temperature-dependent particle mass emission rates of edible oils and to develop models for source strength based on the multiple linear regression method. First, this study examined seven commonly used oils by heating experiments. The emission rates of PM2.5 and PM10 were measured, and the effects of parameters such as oil volume and surface area on the emission rates were also analysed. Following that, the starting smoke points (Ts') and aggravating smoke points (Tss') of tested oils were determined. The results showed that oils with lower smoke points had greater emission rates. Notably, the experiments performed observed that peanut, rice, rapeseed and olive oil generated PM2.5 much faster at 240 °C (2.22, 1.50, 0.82 and 0.80 mg/s, respectively, at the highest emission conditions) than that of sunflower, soybean, and corn oil (0.15, 0.12 and 0.11 mg/s, respectively). The temperature, volume, and surface area of oils all had a significant impact on the particle mass emission rate, with oil temperature being the most influential. The regression models obtained were statistically significant (P < 0.001), with the majority of R2 values greater than 0.85. Using sunflower, soybean and corn oils, which have higher smoke points and lower emission rates, and smaller pans for cooking is therefore recommended based on our research findings.

Systematic mapping of the conformational landscape and dynamism of soluble fibrinogen

BackgroundFibrinogen is a soluble, multisubunit, and multidomain dimeric protein, which, upon its proteolytic cleavage by thrombin, is converted to insoluble fibrin, initiating polymerization that substantially contributes to clot growth. Fibrinogen contains numerous, transiently accessible “cryptic” epitopes for hemostatic and immunologic proteins, suggesting that fibrinogen exhibits conformational flexibility, which may play functional roles in its temporal and spatial interactions. Hitherto, there have been limited integrative approaches characterizing the solution structure and internal flexibility of fibrinogen. MethodsHere, utilizing a multipronged, biophysical approach involving 2 solution-based techniques, temperature-dependent hydrogen-deuterium exchange mass spectrometry and small angle X-ray scattering, corroborated by negative stain electron microscopy, we present a holistic, conformationally dynamic model of human fibrinogen in solution. ResultsOur data reveal 4 major and distinct conformations of fibrinogen accommodated by a high degree of internal protein flexibility along its central scaffold. We propose that the fibrinogen structure in the solution consists of a complex, conformational landscape with multiple local minima. This is further supported by the location of numerous point mutations that are linked to dysfibrinogenemia and posttranslational modifications, residing near the identified fibrinogen flexions. ConclusionThis work provides a molecular basis for the structural “dynamism” of fibrinogen that is expected to influence the broad swath of its functionally diverse macromolecular interactions and fine-tune the structural and mechanical properties of blood clots.

Estimation of the diffusion coefficient of heavy quarks in light of Gribov-Zwanziger action

The heavy quark momentum diffusion coefficient (κ) is one of the most essential ingredients for the Langevin description of heavy quark dynamics. In the temperature regime relevant to the heavy ion collision phenomenology, a substantial difference exists between the lattice estimations of κ and the corresponding leading order (LO) result from the hard thermal loop (HTL) perturbation theory. Moreover, the indication of poor convergence in the next-to-leading order (NLO) perturbative analysis has motivated the development of several approaches to incorporate the non-perturbative effects in the heavy quark phenomenology. In this work, we estimate the heavy quark diffusion coefficient based on the Gribov-Zwanziger prescription. In this framework, the gluon propagator depends on the temperature-dependent Gribov mass parameter, which has been obtained self-consistently from the one-loop gap equation. Incorporating this modified gluon propagator in the analysis, we find a reasonable agreement with the existing lattice estimations of κ within the model uncertainties.

Nuclear shell structure in a finite-temperature relativistic framework

The shell evolution of neutron-rich nuclei with temperature is studied in a beyond-mean-field framework rooted in the meson-nucleon Lagrangian. The temperature-dependent Dyson equation with the dynamical kernel taking into account the particle-vibration coupling (PVC) is solved for the fermionic propagators in the basis of the thermal relativistic mean-field Dirac spinors. The calculations are performed for $^{68-78}$Ni in a broad range of temperatures $0 \leq T \leq 4$ MeV. The special focus is put on the fragmentation pattern of the single-particle states, which is further investigated within toy models in strongly truncated model spaces. Such models allow for quantifying the sensitivity of the fragmentation to the phonon frequencies, the PVC strength and to the mean-field level density. The model studies provide insights into the temperature evolution of the PVC mechanism in real nuclear systems under the conditions which may occur in astrophysical environments.

Low-temperature infrared spectroscopy of the strongly correlated semiconductor Tm0.19Yb0.81B12 with dynamic charge stripes

Tm1–x Yb x B12 dodecaborides represent model objects for the studies of quantum critical behavior, metal–insulator transitions (MITs) and complex charge-spin–orbital–phonon coupling phenomena. In spite of intensive investigations, the mechanism of semiconducting ground state formation both in YbB12 and in the Yb-based strongly correlated electron systems remains a subject of active debates. We have performed first systematic measurements of temperature-dependent spectra of infrared conductivity of Tm0.19Yb81B12 at frequencies 40–35 000 cm−1 and in the temperature range 10–300 K. Analysis of the temperature evolution of the observed absorption resonances is performed allowing to associate these with the cooperative dynamic Jahn–Teller instability of the boron sub-lattice. This ferrodistortive effect of B12-complexes induces the rattling modes of the rare earth ions leading to emergence of both the intra-gap mixed-type collective excitations and the dynamic charge stripes. We estimate the temperature-dependent effective mass of charge carriers and propose the scenario of transformation of the many-body states in the multiple relaxation channels. We attribute the MIT to the localization of electrons at the vibrationally coupled Yb–Yb pairs, which is accompanied by the electronic phase separation and formation of the nanoscale filamentary structure of electron density (stripes) in Tm1–x Yb x B12 compounds.

Desorption characteristics of selenium and tellurium thin films

The temperature-dependent desorption behavior of selenium and tellurium is investigated using a heated quartz crystal microbalance. Prior to heating the quartz crystal microbalance, selenium and tellurium films with varying thickness were deposited using thermal effusion cells in a molecular beam epitaxy system for subsequent determination of temperature-dependent mass loss of the deposited films. The desorption rate for tellurium was found to exhibit one sharp peak around 190 °C, indicating the loss of the entire film irrespective of film thickness within a temperature window of 20 °C, which was completely evaporated at 200 °C. Similar experiments for selenium revealed that the thermal desorption took place via a two-stage process with a smaller portion of the material desorbing within an even narrower temperature window of 5 °C at a much lower peak temperature of 65 °C, while most selenium desorbed within a temperature range of 10 °C around 90 °C. This two-stage behavior indicated the presence of at least two chemically distinct selenium species or binding states. The direct and quantitative determination of the chalcogen desorption process provides important insights into the kinetics of chalcogenide-based film growth and is in addition of applied benefit to the research community in the area of Se/Te capping and decapping of air sensitive materials as it provides temperature ranges and rates at which full desorption is achieved. Our work furthermore points toward the need for a more detailed understanding of the chemical composition state of atomic and molecular beams supplied from thermal evaporation sources during growth.

Temperature-dependent hydrogen deuterium exchange shows impact of analog binding on adenosine deaminase flexibility but not embedded thermal networks

The analysis of hydrogen deuterium exchange by mass spectrometry as a function of temperature and mutation has emerged as a generic and efficient tool for the spatial resolution of protein networks that are proposed to function in the thermal activation of catalysis. In this work, we extend temperature-dependent hydrogen deuterium exchange from apo-enzyme structures to protein–ligand complexes. Using adenosine deaminase as a prototype, we compared the impacts of a substrate analog (1-deaza-adenosine) and a very tight-binding inhibitor/transition state analog (pentostatin) at single and multiple temperatures. At a single temperature, we observed different hydrogen deuterium exchange-mass spectrometry properties for the two ligands, as expected from their 106-fold differences in strength of binding. By contrast, analogous patterns for temperature-dependent hydrogen deuterium exchange mass spectrometry emerge in the presence of both 1-deaza-adenosine and pentostatin, indicating similar impacts of either ligand on the enthalpic barriers for local protein unfolding. We extended temperature-dependent hydrogen deuterium exchange to a function-altering mutant of adenosine deaminase in the presence of pentostatin and revealed a protein thermal network that is highly similar to that previously reported for the apo-enzyme (Gao et al., 2020, JACS 142, 19936-19949). Finally, we discuss the differential impacts of pentostatin binding on overall protein flexibility versus site-specific thermal transfer pathways in the context of models for substrate-induced changes to a distributed protein conformational landscape that act in synergy with embedded protein thermal networks to achieve efficient catalysis.

Properties of AgBiI4 using high through-put DFT and machine learning methods

Silver iodo-bismuthates show promise for optoelectronic and other applications. Within this family of materials, AgBiI4 is a prominent model compound. The complexity of AgBiI4 has prevented a conclusive determination of specific atomic arrangements of metal atoms in the bulk material. Here, we employ high through-put density functional and novel machine learning methods to determine physically relevant unit cell configurations. We also calculate the fundamental properties of the bulk material using newly discovered configurations. Our results for the lattice constant (12.7 Å) and bandgap (1.8 eV) agree with the previous theory and experiment. We report new predictions for the bulk modulus (7.5 GPa) and the temperature-dependent conductivity mass for electrons (m0 at T = 300 K) and holes (7m0 at T = 300 K); these masses will be useful in AgBiI4-based device simulations.

Implications of a Temperature-dependent Initial Mass Function. II. An Updated View of the Star-forming Main Sequence

The stellar initial mass function (IMF) is predicted to depend upon the temperature of gas in star-forming molecular clouds. The introduction of an additional parameter, T IMF, into photometric template fitting, allows galaxies to be fit with a range of IMFs. Three surprising new features appear: (1) most star-forming galaxies are best fit with a bottom-lighter IMF than the Milky Way; (2) most star-forming galaxies at fixed redshift are fit with a very similar IMF; and (3) the most-massive star-forming galaxies at fixed redshift instead exhibit a less bottom-light IMF, similar to that measured in quiescent galaxies. Additionally, since stellar masses and star formation rates both depend on the IMF, these results slightly modify the resulting relationship, while yielding similar qualitative characteristics to previous studies.