Search

Hot axions are produced in the early Universe via their interactions with Standard Model particles, contributing to dark radiation commonly parameterized as ∆Neff. In standard QCD axion benchmark models, this contribution to ∆Neff is negligible after taking into account astrophysical limits such as the SN1987A bound. We therefore compute the axion contribution to ∆Neff in so-called astrophobic axion models characterized by strongly suppressed axion couplings to nucleons and electrons, in which astrophysical constraints are relaxed and ∆Neff may be sizable. We also construct new astrophobic models in which axion couplings to photons and/or muons are suppressed as well, allowing for axion masses as large as few eV. Most astrophobic models are within the reach of CMB-S4, while some allow for ∆Neff as large as the current upper bound from Planck and thus will be probed by the Simons Observatory. The majority of astrophobic axion models predicting large ∆Neff is also within the reach of IAXO or even BabyIAXO. [ABSTRACT FROM AUTHOR]

In this study, existing and promising methods of processing fine fractions and dust of aspiration systems for the production of ferroalloys were analyzed. The technological properties of high-carbon ferrochrome screenings and dust of the ferrochrome crushing aspiration system of the Aktobe Ferroalloy Plant as raw materials for the production of low-carbon ferrochrome briquettes using the vacuum-thermal method were studied. The contents of basic and impurity elements, including gas-forming ones, were determined. The oxygen content in the dust reached 4.2 and 0.12% in the screening. The average size of aspiration dust particles was 9.6 μm, whereas that of the ferrochrome screenings was 1.44 mm. In the dust and screening samples, the main phase was Cr7C3, and graphite was present in the dust sample. During thermal analysis, the dust sample completely melted at 1453 °C, and a liquid phase was not observed when ferrochrome was heated. At 1340 °C, the formation of iron silicide was noted. With increasing temperature, the concentrations of carbon and chromium carbide decreased. From thermodynamic calculations, recommendations were given on the parameters of vacuum-thermal decarburization of high-carbon ferrochrome. The results of preliminary experiments confirmed the possibility of removing carbon from screenings and aspiration dust. From samples containing 9.04–9.11% carbon, ferrochrome with a content of 0.10% carbon could be obtained. At the next stage of our work, we plan to work out in detail the parameters affecting the vacuum-heat treatment of ferrochrome. We assume that ferrochrome with a carbon content of 0.00x% can be obtained. [ABSTRACT FROM AUTHOR]

Most production methods of heavy oil involve thermal production. However, it is challenging to delineate the thermal-affected zone due to complex reservoir conditions. With steam injected, the heavy oil viscosity drops; the reservoir density and velocity decrease accordingly, causing changes to seismic impedance. Moreover, the oil-and-water viscosity ratio and permeability show the difference with changing temperature, indicating that the reservoir's ability to transmit seismic waves would also be temperature-dependent. Therefore, the seismic responses and attenuation characteristics of the steam chamber can be helpful to monitor the steam-affected zone. We introduce an improved viscoelastic model to approximate the heavy oil reservoir during thermal production, and use the frequency-space domain finite difference algorithm to simulate the seismic wave-fields. Numerical results demonstrate that this model is applicable to a wide temperature range, and can effectively reveal the seismic characteristics of the steam chamber. Through analyzing the propagation differences of seismic waves under different temperatures, it is concluded that the attenuation coefficient, root-mean-square amplitude difference and amplitude ratio of PP-wave and PS-wave under different conditions can reveal the temperature variation in the steam chamber, with which it is possible to detect the steam chamber spatial distribution. [ABSTRACT FROM AUTHOR]

A very simple production mechanism of feebly interacting dark matter (DM) that rarely annihilates is thermal production, which predicts the DM mass around eV. This has been widely known as the hot DM scenario. Despite there are several observational hints from background lights suggesting a DM in this mass range, the hot DM scenario has been considered strongly in tension with the structure formation of our Universe because the free-streaming length of the DM produced from thermal reactions was thought to be too long. In this paper, I show that the previous conclusions are not always true depending on the reaction for bosonic DM because of the Bose-enhanced reaction at very low momentum. By utilizing a simple 1 ↔ 2 decay/inverse decay process to produce DM, I demonstrate that eV range bosonic DM can be thermally produced in a cold manner from a hot plasma through a model-independent analysis applicable to axion, hidden photon, and other bosonic DM candidates. As a result, bosonic DM in the eV mass range may still be unique and theoretically well-motivated. I also discuss some caveats arising from this phenomenon in the freeze-in production of DM, and present a related system that can suppress the hot plasma with thermal reaction. [ABSTRACT FROM AUTHOR]

In the process of thermal recovery of heavy oil, the casing in oil production wells is subjected to complex stress conditions, which may cause potential damage and affect the lifecycle of the casing. The factors influencing the casing instability and the mechanism of the process in thermal production wells need to be comprehensively researched, particularly in the case where oil extraction is accompanied by sand production. In this paper, the authors have applied the three-dimensional finite element method to simulate the casing instability characteristics in the sand production section of a thermal recovery well. We have also analyzed the effect of sand production, perforation parameters, and the casing strength parameters on the axial and circumferential instability of the casing. The results show that sand production can cause a significant decrease in the lateral support of the casing and greatly reduce the buckling resistance of the casing in a thermal horizontal well. With increase in perforation diameter and perforation density, the critical buckling load of the casing decreases. On the other hand, the buckling load is less affected by the perforation phase. When the combination of the perforation density and perforation phase angle results in a bigger number of perforation holes in the row, it can significantly reduce the casing collapse strength and increase the risk of circumferential instability. The research results provide a theoretical basis in the design of casing in horizontal sections of thermal production wells. [ABSTRACT FROM AUTHOR]

A pseudo Nambu-Goldstone boson (pNGB) is a natural candidate of dark matter in that it avoids the severe direct detection bounds. We show in this paper that the pNGB has another different and interesting face with a higher symmetry breaking scale. Such large symmetry breaking is motivated by various physics beyond the standard model. In this case, the pNGB interaction is suppressed due to the Nambu-Goldstone property and the freeze-out production does not work even with sufficiently large portal coupling. We then study the pNGB dark matter relic abundance from the out-of-equilibrium production via feeble Higgs portal coupling. Further, a possibility is pursued the symmetry breaking scalar in the pNGB model plays the role of inflaton. The inflaton and dark matter are unified in a single field and the pNGB production from inflaton decay is inevitable. For these non-thermally produced relic abundance of pNGB dark matter and successful inflation, we find that the dark matter mass should be less than a few GeV in the wide range of the reheating temperature and the inflaton mass. [ABSTRACT FROM AUTHOR]

The article focuses on the thermal production of fluorine radicals. It talks about the low bond energy of the fluorine molecule, which enables the molecule to get dissociated into radicals. It explores the application of this concept in nuclear engineering, wherein the radicals are formed in the gaseous phase using heterogeneous fluorination method.

Hardening technologies have been developed for medium-carbon alloyed steels in the system of integrated deformation-thermal production. The results of industrial testing using the equipment complex on a reversing mill 2000 are given. [ABSTRACT FROM AUTHOR]

Physical simulation of a process of production of tube strip steels of strength category X80 for large-diameter oil and gas transportation tubes is performed. Mechanical properties of the steels are determined. Two processes (basic and alternative ones) are suggested for making strips of strength category X80. [ABSTRACT FROM AUTHOR]

The influence of plastic deformation (creep) of corrosion-resistant 10Kh23N18, 04Kh18N10Т, and AISI 321 steels on the decrease in the thickness of the shell wall and the intensification of corrosion fracture processes is investigated. The comparative evaluation of the materials used in the retort production is performed. It is shown that the application of 10Kh23N18 steel with improved creep characteristics increases the service life of the retorts from 35 to 43 cycles. [ABSTRACT FROM AUTHOR]

A porous anodic alumina sample with ordered channels was studied in order to characterise its efficiency as a positron-positronium converter at cryogenic temperatures. The effects of gas adsorption were found to be vacuum dependent and considerable up to 200 nm depth inside the sample. At higher depths it was possible to identify a temperature dependent positronium formation mechanism and the related activation energy was determined to be in an interval from 8.7 to 16 meV. Because of this mechanism the Ps yield decreases to a few percent with decreasing temperature and it can be considered unsuitable for an efficient cryogenic positronium production. [ABSTRACT FROM AUTHOR]

The thermal multihadron production observed in different high energy collisions poses two basic problems. (1) Why do even elementary collisions with comparatively few secondaries ( e + e − annihilation) show thermal behavior? (2) Why is there in such interactions a suppression of strange particle production? We show that the recently proposed mechanism of thermal hadron production through Hawking–Unruh radiation can naturally account for both. The event horizon of color confinement leads to thermal behavior, but the resulting temperature depends on the strange quark content of the produced hadrons, causing a deviation from full equilibrium and hence a suppression of strange particle production. We apply the resulting formalism to multihadron production in e + e − annihilation over a wide energy range and make a comprehensive analysis of the data in the conventional statistical hadronization model and the modified Hawking–Unruh formulation. We show that this formulation provides a very good description of the measured hadronic abundances, fully determined in terms of the string tension and the bare strange quark mass; it contains no adjustable parameters. [ABSTRACT FROM AUTHOR]

For process–structure simulation, a lot of models and methods have been created and implemented into different software systems. The uncontrolled growth of specific solutions has led to a bewilderment for (potential) users during the last years. Therefore, the most important step before choosing and applying a method for modeling is to define the task of each simulation clearly and, in addition, to analyze the general conditions. In this paper, a systematic classification of all relevant influences for a part-specific simulation by means of the Finite Element Method (FEM) concerning thermal production processes is presented. Relating to a certain scenario, this classification helps to choose adequate models. Combined with the experience and the theoretical background of the user, the dilemma of efficiency in application and the accuracy of the results can be solved satisfactorily for each task. [ABSTRACT FROM AUTHOR]

Self-Interacting Dark Matter models can successfully explain dark matter (DM) production through interactions confined within the dark sector. However, they often lack measurable experimental signals due to their secluded nature. Including a feeble interaction with the visible sector through a Higgs portal leads not only to potential detection avenues and richer thermal production dynamics, but also to a possible explanation of the initial dark sector population through the freeze-in mechanism. In this work we study, by solving the full system of coupled Boltzmann equations for the number densities and temperatures of all the involved states, three scenarios of this type where the DM is: a real scalar with broken ℤ2, a complex scalar with unbroken ℤ3, and a ℤ3 scalar with an additional scalar mediator. All of these models have viable dark matter candidates in a cannibal phase while having different detection profiles. We show that cosmological bounds can be either exacerbated or evaded by changing the dark sector interactions, leading to potential signatures in long-lived particle and indirect detection experiments. [ABSTRACT FROM AUTHOR]

We present a new scenario of gravitino dark matter which is compatible with the thermal leptogenesis. We confirm by an explicit calculation in supergravity that the relic abundance of thermally produced gravitino becomes insensitive to the reheating temperature once the temperature of the Universe exceeds the mass scale of the messenger fields. In such a situation, the correct baryon to dark matter ratio can be obtained by thermal leptogenesis when the reheating temperature after inflation is high enough. We demonstrate in a concrete model of gauge mediation that the correct abundance of gravitino and baryon asymmetry can be reproduced by considering the late-time entropy production from the decay of the SUSY-breaking pseudo-moduli field. The scenario is realized when the gravitino mass is 100MeV ≲ m3/2 ≲ 1GeV, and the messenger mass scale is 106 GeV ≲ Mmess ≲ 109 GeV. [ABSTRACT FROM AUTHOR]

Results on the transverse spherocity dependence of light-flavor particle production (π, K, p, ϕ, K*0, K S 0 , Λ, Ξ) at midrapidity in high-multiplicity pp collisions at s = 13 TeV were obtained with the ALICE apparatus. The transverse spherocity estimator S O p T = 1 categorizes events by their azimuthal topology. Utilizing narrow selections on S O p T = 1 , it is possible to contrast particle production in collisions dominated by many soft initial interactions with that observed in collisions dominated by one or more hard scatterings. Results are reported for two multiplicity estimators covering different pseudorapidity regions. The S O p T = 1 estimator is found to effectively constrain the hardness of the events when the midrapidity (|η| < 0.8) estimator is used. The production rates of strange particles are found to be slightly higher for soft isotropic topologies, and severely suppressed in hard jet-like topologies. These effects are more pronounced for hadrons with larger mass and strangeness content, and observed when the topological selection is done within a narrow multiplicity interval. This demonstrates that an important aspect of the universal scaling of strangeness enhancement with final-state multiplicity is that high-multiplicity collisions are dominated by soft, isotropic processes. On the contrary, strangeness production in events with jet-like processes is significantly reduced. The results presented in this article are compared with several QCD-inspired Monte Carlo event generators. Models that incorporate a two-component phenomenology, either through mechanisms accounting for string density, or thermal production, are able to describe the observed strangeness enhancement as a function of S O p T = 1 . [ABSTRACT FROM AUTHOR]

A computational analysis of convective energy transport of water-based nanosuspension having variable thermal properties has been performed using finite difference method. The considered square cavity includes cold vertical walls and adiabatic horizontal boundaries. The local heater of periodic thermal production is placed on the lower border of the domain. The working fluid is water with copper oxide nanoparticles of low concentration. Control differential equations with initial and boundary conditions have been written using non-dimensional stream function, vorticity and temperature. The resulting nonlinear partial differential equations with associated boundary conditions are solved using the finite difference methodology on a uniform calculation mesh. The analyzed control parameters including volumetric heat generation frequency, initial fraction of nanoparticles, heater location and time have been studied. The physics of the problem is well-explored for the embedded material parameters through tables and graphs. The obtained data have shown that the volumetric thermal production frequency of the source and the initial concentration of nanoparticles have the greatest influence on the heat transfer performance. The energy source temperature can be reduced by up to 20% by varying the characteristics of the source and nanosuspension. [ABSTRACT FROM AUTHOR]

Gravitational production of massive particles due to cosmic expansion can be significant during the inflationary and reheating period of the Universe. If the particle also has non-gravitational interactions that do not significantly affect its production, numerous observational probes open up, including cosmological probes. In this work, we focus on the gravitational production of light vector bosons that couple feebly to the Standard Model (SM) particles. Due to the very feeble coupling, the light vector bosons never reach thermal equilibrium, and if the Hubble scale at the end of inflation is above 108 GeV, the gravitational production can overwhelm the thermal production via the freeze-in mechanism by many orders of magnitude. As a result, much stronger constraints from the Big Bang Nucleosynthesis (BBN) can be placed on the lifetime and mass of the vector bosons compared to the scenario where only thermal production is considered. As an example, we study the sub-GeV scale dark photons, which couple to the SM only through kinetic mixing, and derive constraints on the mass and kinetic mixing parameter of the dark photon from the photodisintegration effects on the light element abundances relevant at the end of the BBN when the cosmic age was around 104 s. [ABSTRACT FROM AUTHOR]

The angular correlations between charged Ξ baryons and associated identified hadrons (pions, kaons, protons, Λ baryons, and Ξ baryons) are measured in pp collisions at s = 13 TeV with the ALICE detector to give insight into the particle production mechanisms and balancing of quantum numbers on the microscopic level. In particular, the distribution of strangeness is investigated in the correlations between the doubly-strange Ξ baryon and mesons and baryons that contain a single strange quark, K and Λ. As a reference, the results are compared to Ξπ and Ξp correlations, where the associated mesons and baryons do not contain a strange valence quark. These measurements are expected to be sensitive to whether strangeness is produced through string breaking or in a thermal production scenario. Furthermore, the multiplicity dependence of the correlation functions is measured to look for the turn-on of additional particle production mechanisms with event activity. The results are compared to predictions from the string-breaking model Pythia 8, including tunes with baryon junctions and rope hadronisation enabled, the cluster hadronisation model Herwig 7, and the core-corona model Epos-lhc. While some aspects of the experimental data are described quantitatively or qualitatively by the Monte Carlo models, no model can match all features of the data. These results provide stringent constraints on the strangeness and baryon number production mechanisms in pp collisions. [ABSTRACT FROM AUTHOR]

Due to high-ultra thermic significances, the nanosize materials are used in various chemical and mechanical engineering, modern technology and thermic engineering eras. For industrial growth of a country, one of the biggest challenges for engineers and scientists is improvement in thermal production and resources. In this study we analyzed the momentum and thermic aspects of MHD Ellis ternary nano material embedded with dust particles via stretchable Riga plate including volume concentration of dust material. The flow generating PDE's for two phase models are minimized into dimensionless nonlinear ODE's by using the right modification. To acquire the graphical results the BVP4c method was adopted in MATLAB software. Fundamental aspects affecting velocity and temperature have investigated through graphs. Additionally Nusselt number and skin friction have also been evaluated. Compared it with previous literature to check the validity of results. Finding reveals that as compared to dusty phase the performance of trihybrid nano phase thermal transport is improved. Moreover, the temperature profile increases for rotational and volume fraction dust particles parameter. Dusty fluids are used in numerous manufacturing and engineering sectors, like petroleum transport, car smoke emissions, caustic granules in mining and power plant pipes. [ABSTRACT FROM AUTHOR]

Parabolic trough collectors (PTCs) are the most advanced and widely used technology in solar concentrating systems. However, their high-cost and high-technology requirements for parabolic mirror manufacturing constituted real shortcomings for their implementation in low-income countries, which urged the need for finding replacements for them. This study assessed the performance of two small-scale solar thermal production units, namely a semi-parabolic linear Fresnel reflector (SPLFR) and a PTC with stainless-steel (PTC-SS) sheet reflector as alternatives for PTCs. The impact of tracking, surface, and displacement errors and reflectivity on the flux distribution and uniformity index were investigated for both designs. Firstly, it was observed that PTC-SS presented a better intercept factor compared to SPLFR for 1° tracking error. Secondly, a displacement error of 6.2 mm seemed to have a significant effect on the performance of SPLFR and a slight effect on that of PTC-SS reflector. Thirdly, the optical efficiency for SPLFR reached 77.8% of the available solar flux while that of PTC-SS reflector reached 71.3%. Fourthly, an experimental test confirmed that the overall efficiency of SPLFR is better than that of PTC-SS. Consequently, SPLFR would be a better potential alternative to conventional PTC for low-income countries because of its rather acceptable performance, easier manufacture, low cost, use of recyclable mirrors as well as its more uniform flux shape in the receiver circumference. [ABSTRACT FROM AUTHOR]

Electricity systems are quitting monopoly for an operation framed by competitive markets. It therefore questions how the operation of nuclear plants capable of load-following is expected to change at the transition stage in a challenging economic environment for nuclear producers given the high penetration of renewables and the increase of nuclear production costs for renovation and safety reasons. To answer this question, we are focusing on a month-by-month management horizon of the nuclear fuel given the technico-economical features of the operation of flexible nuclear plants. The resolution of the month-by-month profit maximization problem contributes to identify potential difficulties and limits of production optimization and provides us with an equilibrium which proves the existence of an optimal production path. This benchmark could serve as a reference providing valuable insight on the resolution of more complex optimisation problems. [ABSTRACT FROM AUTHOR]

We examine the singlet-doublet fermionic dark matter model, where the non-thermal production of the dark matter in light of a non-standard cosmology demands a significantly large interaction rate than the typical radiation-dominated Universe. Despite being a model of freeze-in light dark matter and heavy mediator, the characteristic long-lived particle searches at the collider experiment and the displaced vertex signature do not help in probing such a dark sector since this non-standard interaction mandates nearly prompt decay. We make a counterproposal to probe such signal with di-fat-jets generated from the boosted decays of massive vector bosons and Standard Model Higgs, along with the substantial missing transverse momentum to probe the dark matter at LHC. Interestingly, substructure variables associated with these fat jets have an additional handle to tackle the extensive QCD background as it encodes implicit footmarks of their origin. We adopt the multivariate analysis with the booted decision tree to constrain the measured relic density allowed parameter space of dark matter in the presence of the modified cosmological scenario. Our study shows how the non-trivial expansion affects dark matter production in the early Universe and alters the required search strategies at colliders. This probe provides the best discovery prospect at the HL-LHC for extended parameter space now opened up in the dark sector. [ABSTRACT FROM AUTHOR]

Ultra-low mass primordial black holes (PBH), which may briefly dominate the energy density of the universe but completely evaporate before the big bang nucleosynthesis (BBN), can lead to interesting observable signatures. In our previous work, we studied the generation of a doubly peaked spectrum of induced stochastic gravitational wave background (ISGWB) for such a scenario and explored the possibility of probing a class of baryogenesis models wherein the emission of massive unstable particles from the PBH evaporation and their subsequent decay contributes to the matter-antimatter asymmetry. In this work, we extend the scope of our earlier work by including spinning PBHs and consider the emission of light relativistic dark sector particles, which contribute to the dark radiation (DR) and massive stable dark sector particles, thereby accounting for the dark matter (DM) component of the universe. The ISGWB can probe the non-thermal production of these heavy DM particles, which cannot be accessible in laboratory searches. For the case of DR, we find a novel complementarity between the measurements of ∆Neff from these emitted particles and the ISGWB from PBH domination. Our results indicate that the ISGWB has a weak dependence on the initial PBH spin. However, for gravitons as the DR particles, the initial PBH spin plays a significant role, and only above a critical value of the initial spin parameter a*, which depends only on initial PBH mass, the graviton emission can be probed in the CMB-HD experiment. Upcoming CMB experiments such as CMB-HD and CMB-Bharat, together with future GW detectors like LISA and ET, open up an exciting possibility of constraining the PBHs parameter space providing deeper insights into the expansion history of the universe between the end of inflation and BBN. [ABSTRACT FROM AUTHOR]

We investigate the thermal production rates for charmonium as a signal for the presence of a gluon plasma using two different models describing the plasma formation. [ABSTRACT FROM AUTHOR]

In the early universe, Dirac neutrino magnetic moments due to their chirality-flipping nature could lead to thermal production of right-handed neutrinos, which would make a significant contribution to the effective neutrino number, Neff. We present in this paper a dedicated computation of the neutrino chirality-flipping rate in the thermal plasma. With a careful and consistent treatment of soft scattering and the plasmon effect in finite temperature field theories, we find that neutrino magnetic moments above 2.7 × 10−12μB have been excluded by current CMB and BBN measurements of Neff, assuming flavor-universal and diagonal magnetic moments for all three generation of neutrinos. This limit is stronger than the latest bounds from XENONnT and LUX-ZEPLIN experiments and comparable with those from stellar cooling considerations. [ABSTRACT FROM AUTHOR]

We revisit the thermal production and annihilation of magnetic monopoles and their relic abundance in order to gain a deeper physical interpretation on the monopole phenomenology predicted from the Baines et al.'s effective field theory, recently proposed in the description of monopole pair production via Drell–Yan and photon fusion processes. In this sense, we use of the vacuum cross sections for the Drell–Yan reactions derived within the mentioned framework to evaluate the cross section averaged over the thermal distribution associated to other particles that constitute the hot medium where the monopoles propagate. In the considered range of monopole mass with spin-zero and spin-half, our findings suggest that the thermally averaged cross sections for the pair production are highly suppressed, while at higher temperatures those for the annihilation of lighter pairs reach larger magnitudes. Besides, we observe that smaller temperature leads to a rate of annihilation for scalar monopoles smaller than the one for fermionic monopoles, which might be interpreted as a theoretical evidence of a more pronounced stability for spin-zero and heavier monopoles. Then we input these thermally averaged cross sections into the kinetic equation that describes the evolution of the monopole abundance via an extension of a freeze-out theory. Our results infer that heavier monopoles achieve the equilibrium at earlier stages of the expansion, and consequently at higher temperatures. In addition, larger monopole masses produce higher values of the relic abundance. Besides, the results indicate that the abundance does not behave differently for spin-zero and spin-half relic monopoles. [ABSTRACT FROM AUTHOR]

Over the past 60 years a rich sample of experimental results concerning the inclusive production of π - mesons has been obtained spanning a range from about 3 GeV to 13 TeV in interaction energy. This paper attempts a model-independent overview of these results with the aim at obtaining an internally consistent data description on a dense grid over the three inclusive variables transverse momentum, rapidity or Feynman x F and interaction energy. The study concentrates on the non-perturbative sector of the strong interaction by limiting the transverse momenta to p T < 1.3 GeV/c. The three-dimensional interpolation which is mandatory and necessary for this aim is shown to provide a controlled systematic precision of better than 5%. This accuracy allows for a critical inspection of each of the 40 experiments concerned in turn. It also allows precision tests of some of the physics concepts developed around inclusive processes like energy scaling, "thermal" production and the evolution of transverse momenta. [ABSTRACT FROM AUTHOR]

We investigate for viable models of inflation that can successfully produce dark matter (DM) from inflaton decay process, satisfying all the constraints from Cosmic Microwave Background (CMB) and from some other observations. In particular, we analyze near-inflection-point small field inflationary scenario with non-thermal production of fermionic DM from the decaying inflaton field during the reheating era. To this end, we propose two different models of inflation with polynomial potential. The potential of Model I contains terms proportional to linear, quadratic, and quartic in inflaton; whereas in Model II, the potential contains only even power of inflaton and the highest term is sextic in inflaton. For both the models, we find out possible constraints on the model parameters which lead to proper inflationary parameters from CMB data with a very small tensor-to-scalar ratio, as expected from a small-field model. With the allowed parameter space from CMB, we then search for satisfactory relic abundance for DM, that can be produced from inflaton via reheating, to match with the present-day cold dark matter (CDM) relic density for the parameter spaces of the DM χ mass and Yukawa couplings in the range 10−9 ≳ yχ ≳ 10−15 and 103GeV ≲ mχ ≲ 109GeV. The DM relic is associated with the inflection-points in each model via maximum temperature reached in the early universe during its production. Finally, we find out allowed parameter space coming out of combined constraints from stability analysis for both SM Higgs and DM decays from inflaton as well as from BBN and Lyman-α bounds. [ABSTRACT FROM AUTHOR]

In this work we explore the intriguing connections between searches for long-lived particles (LLPs) at the LHC and early universe cosmology. We study the non-thermal production of ultra-relativistic particles (i.e. dark radiation) in the early universe via the decay of weak-scale LLPs and show that the cosmologically interesting range ∆Neff ~ 0.01–0.1 corresponds to LLP decay lengths in the mm to cm range. These decay lengths lie at the boundary between prompt and displaced signatures at the LHC and can be comprehensively explored by combining searches for both. To illustrate this point, we consider a scenario where the LLP decays into a charged lepton and a (nearly) massless invisible particle. By reinterpreting searches for promptly decaying sleptons and for displaced leptons at both ATLAS and CMS we can then directly compare LHC exclusions with cosmological observables. We find that the CMB-S4 target value of ∆Neff = 0.06 is already excluded by current LHC searches and even smaller values can be probed for LLP masses at the electroweak scale. [ABSTRACT FROM AUTHOR]

We consider the gauged B − L model which is extended with a secluded dark sector, comprising of two dark sector particles. In this framework the lightest Z 2-odd particle is the dark matter candidate, having a feeble interaction with all other SM and BSM states. The next-to-lightest Z 2-odd particle in the dark sector is a super-wimp, with large interaction strength with the SM and BSM states. We analyse all the relevant production processes that contribute to the dark matter relic abundance, and broadly classify them in two different scenarios, a) dark matter is primarily produced via the non-thermal production process, b) dark matter is produced mostly from the late decay of the next-to-lightest Z 2-odd particle. We discuss the dependency of the relic abundance of the dark matter on various model parameters. Furthermore, we also analyse the discovery prospect of the BSM Higgs via invisible Higgs decay searches. [ABSTRACT FROM AUTHOR]

An advanced cogeneration system based on biomass direct combustion was developed and its feasibility was demonstrated. In place of the traditional single heat source (extraction steam), the extraction steam from the turbine, the cooling water from the plant condenser, and the low-pressure feedwater from the feedwater preheating system were collectively used for producing district heat in the new scheme. Hence, a remarkable energy-saving effect could be achieved, improving the overall efficiency of the cogeneration system. The thermodynamic and economic performance of the novel system was examined when taking a 35 MW biomass-fired cogeneration unit for case study. Once the biomass feed rate and net thermal production remain constant, an increment of 1.36 MW can be expected in the net electric production, because of the recommended upgrading. Consequently, the total system efficiency and effective electrical efficiency augmented by 1.23 and 1.50 percentage points. The inherent mechanism of performance enhancement was investigated from the energy and exergy aspects. The economic study indicates that the dynamic payback period of the retrofitting project is merely 1.20 years, with a net present value of 5796.0 k$. In conclusion, the proposed concept is validated to be advantageous and profitable. [ABSTRACT FROM AUTHOR]

The fast developments of radio astronomy open a new window to explore the properties of Dark Matter (DM). The recent direct imaging of the supermassive black hole (SMBH) at the center of M87 radio galaxy by the Event Horizon Telescope (EHT) collaboration is expected to be very useful to search for possible new physics. In this work, we illustrate that such results can be used to detect the possible synchrotron radiation signature produced by DM annihilation from the innermost region of the SMBH. Assuming the existence of a spike DM density profile, we obtain the flux density due to DM annihilation induced electrons and positrons, and derive new limits on the DM annihilation cross section via the comparison with the EHT integral flux density at 230 GHz. Our results show that the parameter space can be probed by the EHT observations is largely complementary to other experiments. For DM with typical mass regions of being weakly interacting massive particles, the annihilation cross section several orders of magnitude below the thermal production level can be excluded by the EHT observations under the density spike assumption. Future EHT observations may further improve the sensitivity on the DM searches, and may also provide a unique opportunity to test the interplay between DM and the SMBH. [ABSTRACT FROM AUTHOR]

Thermal axion production in the early universe goes through several mass thresholds, and the resulting rate may change dramatically across them. Focusing on the KSVZ and DFSZ frameworks for the invisible QCD axion, we perform a systematic analysis of thermal production across thresholds and provide smooth results for the rate. The QCD phase transition is an obstacle for both classes of models. For the hadronic KSVZ axion, we also deal with production at temperatures around the mass of the heavy-colored fermion charged under the Peccei-Quinn symmetry. Within the DFSZ framework, standard model fermions are charged under this symmetry, and additional thresholds are the heavy Higgs bosons masses and the electroweak phase transition. We investigate the cosmological implications with a specific focus on axion dark radiation quantified by an effective number of neutrino species and explore the discovery reach of future CMB-S4 surveys. [ABSTRACT FROM AUTHOR]

Enhanced geothermal system technology is in the focus of geothermal energy research due to its large economic growth potential. This study illustrates a pseudo-3D doublet model of EGS using coupled thermo-hydro-mechanical-damage modeling processes in the framework of TOUGHREACT-FLAC3D. Three cases were simulated to evaluate the effect of anisotropic permeability (η=5, 1, 0.2) on conducting damage, inducing permeability evolution, reducing elastic module, changing reservoir pressure, and thermal power output. The results show that the overall damage zone decreases with the enhancement of anisotropic permeability ratio η, for η=5, the damage zone increases with time, and the damage breakthrough appears earlier than the other cases. The fracture permeability of model is obviously affected by the evolution of rock damage and the degradation of elastic modulus, which is the main reason to induce rock damage. The injection-production pressure difference is another factor to rock damage except for thermal stress, which becomes the dominated factor as the model with a lower value of η, and injection-production pressure difference may be more influential to the model with low anisotropic permeability η. There is a threshold of permeability anisotropy ratio to balance the above two factors. Comparing the performance of thermal power output in various cases, the increasing reservoir permeability can be controlled to favorable for increasing the efficiency and production of thermal in a short time. From the perspective of whole reservoir lifetime, the effect of injection-production pressure difference on increasing the thermal production is more evident. [ABSTRACT FROM AUTHOR]

In this paper we present a novel mechanism for producing the observed Dark Matter (DM) relic abundance during the First Order Phase Transition (FOPT) in the early universe. We show that the bubble expansion with ultra-relativistic velocities can lead to the abundance of DM particles with masses much larger than the scale of the transition. We study this non-thermal production mechanism in the context of a generic phase transition and the electroweak phase transition. The application of the mechanism to the Higgs portal DM as well as the signal in the Stochastic Gravitational Background are discussed. [ABSTRACT FROM AUTHOR]

We study a dark matter model constructed by extending the standard model with an inert SU(2)L sextuplet scalar of hypercharge 1/2. The sextuplet components are split by the quartic couplings between the sextuplet and the Higgs doublet after electroweak symmetry breaking, resulting in a dark sector with one triply charged, two doubly charged, two singly charged, and two neutral scalars. The lighter neutral scalar boson acts as a dark matter particle. We investigate the constraints on this model from the monojet + and soft-dilepton + jets + searches at the 13 TeV Large Hadron Collider, as well as from the current electroweak precision test. Furthermore, we estimate the projected sensitivities of a 100 TeV pp collider and of a future e+e− collider, and find that such future projects could probe TeV mass scales. Nonetheless, such mass scales only correspond to a subdominant component of the observed relic abundance if the dark matter particles solely originate from thermal production. [ABSTRACT FROM AUTHOR]

This article aims to employ an analytical approach to analyze the thermal and mechanical responses of biological tissues due to instant heating, considering the dual phase-lag (DPL) model. To effectively carry out thermal treatment procedures, it is imperative to have a deep understanding of both the mechanism of heat transmission and the resulting thermomechanical interactions within the patient's human tissues. The governing formulations of this extended bio-thermoelastic model are established using analytical methods and Laplace transforms. The eigenvalue approach is then employed to obtain solutions to these formulations. The results for temperature, displacement and stresses are presented graphically. A comparative analysis has been conducted between two bioheat transfer models: the DPL and the Pennes bioheat (Pennes) models. [ABSTRACT FROM AUTHOR]

The demand for energy and renewable energy utilization increases swiftly and accelerates technological development in the renewable field. Still, there is a lack of awareness and government policy that may boost capacity addition. In order to address the challenges presented by the unpredictable and intermittent character of renewable energy sources (RES), the utilization of RES in conjunction with their associated expenses has the potential to provide an affordable, environmentally friendly, and efficient alternative energy supply. This study centers on the techno-economic evaluation of hybrid renewable energy systems (HRESs) used for electricity production through Solid wastes. The present study explores the benefits of a grid-connected Hybrid Renewable Energy System over stand-alone HRES via Solid waste management due to technological and policy improvements. Furthermore, net metering and bill savings through self-consumption and sensitivity analysis for five different sell-back prices. The impact of sensitivity analysis on HRES economics is discussed in this paper. A commercially available software, HOMER@ pro, simulates the system for the optimal solution. The result shows that the stand-alone system's economy is high if there is an absence of sell-back from the consumer's end. Whereas, with the sell-back price introduction, the economy of the grid-interactive HRES is too low and trending to be minimal. Moreover, the study concludes that net metering with the sell-back price reduces the Net Present Value and Cost of Energy, i.e., sell-back price of Rs.2/kWh; the cost of energy production is Rs.1.43/kWh. Due to the sell from the consumer ends, the system generates yearly earnings, which is highest (Rs.133,920/year) in case of a sell-back price of Rs.2/kWh. Therefore, the installation of a Hybrid Renewable Energy System (HRES) tailored to the specific climatic circumstances would provide a durable and reliable and affordable energy solution that effectively addresses climate concerns, enhances energy stability, and promotes ecological accountability supporting SDG goals. [ABSTRACT FROM AUTHOR]

Direct-drive laser inertial fusion is a potential producer of baseline power that has increased credibility following the achievement at the National Ignition Facility of ignition and net gain using indirect-drive via laser-produced X-rays. Ultraviolet broad band lasers such as argon fluoride, at 193 nm and 10 THz, are predicted by hydrocode simulations to enable energy gains greater than 100 with laser energies less than 0.5 MJ, stimulating renewed reactor design effort in anticipation of experimental verification. The present study attempts to create a reactor design with very few unknowns in materials, corrosion, first wall viability, tritium breeding and ease of servicing. A new variant of magnetic intervention has an increased ion dump surface area combined with a simple structure. Around an inner vacuum vessel an all-ceramic tritium breeder blanket is possible in an unconstrained volume, allowing helium coolant to be used without excessive pressure or flow power. The case is made for development of a lead (Pb) ceramic as the neutron multiplier. [ABSTRACT FROM AUTHOR]

The limitation of renewable energy is its fluctuation with time, season, and peak load demand. Hence, most of the research was carried using demand side management to reduce the actual consumption load to lower the peak load. This will also hamper the basic energy need of the facility. Therefore, the objective of the present study is to model a hybrid renewable energy system (HRES) to attain the specific consumption of a community health centre (CHC) in Yomcha, Arunachal Pradesh, with load shedding. The optimization of HRES is performed on HOMER® Pro software along with the demand side management algorithm and a maximum annual capacity shortage of 5%. Three different cases were compared based on feasibility, economics, and environmental basis to estimate the performance of the HRES. The results show that the proposed model is appropriate for the CHC over the previously proposed system. Moreover, HRES with (design-side management) DSM will reduce the overall cost and increase efficiency and reliability with an net present value of Rs. 3013482 and a cost of energy of Rs. 5.42/kW, renewable fraction 78%, internal rate of return 70%, return of investment 66%, and payback period of 1.4 years. Moreover, it reduces emissions, controls overloading during peak hours, and decreases load shifting. The study also supports the sustainable development goal (SDG)-7 set by the United Nation SDG Committee. [ABSTRACT FROM AUTHOR]

We study Dark Matter production during first order phase transitions from bubble-plasma collisions. We focus on scenarios where the Dark Matter sector is secluded and its interaction with the visible sector (including the Standard Model) originates from dimension-five and dimension-six operators. We find that such DM is generally heavy and has a large initial velocity, leading to the possibility of DM being warm today. We differentiate between the cases of weakly and strongly coupled dark sectors, where, in the latter case, we focus on glueball DM, which turns out to have very distinct phenomenological properties. We also systematically compute the Freeze-In production of the dark sector and compare it with the bubble-plasma DM abundances. [ABSTRACT FROM AUTHOR]

This work is devoted to the search for lambda hyperons and short-lived neutral kaons born in nuclear collisions in the Baryonic Matter at Nuclotron (BM@N) experiment, implemented at the Joint Institute for Nuclear Research (JINR, Dubna). To analyze the influence of different sources on the effectiveness of strange particle reconstruction algorithms, Monte Carlo simulations of the collision of a 3.9 AGeV Xe beam with a CsI target were used. After reconstruction of events and selection of candidate pairs, distributions of invariant masses were obtained and peaks corresponding to lambda hyperons and neutral kaons were identified. An analysis of the impact of each of the sources on the reduction of reconstruction efficiency was performed. [ABSTRACT FROM AUTHOR]

In this work, we investigate the effects of first-order phase transitions on the singlet fermionic dark matter in the scotogenic model. It is known that this dark matter candidate tends to conflict with the relevant constraints such as the neutrino oscillation data and charged lepton flavor violating processes if its thermal production mechanism is assumed. We find that the dark matter production mechanisms are modified by first-order phase transitions at some specific parameter regions, where the phase transitions can be one-step or two-step depending on the parameters. If the phase transition is one-step, a sufficiently low nucleation temperature is required to reproduce the observed relic abundance of dark matter. If the phase transition is two-step, the dark matter should never be thermalized, otherwise the abundance would remain too much and overclose the universe. This is because the nucleation temperature cannot be low as in the one-step case. Therefore we require another way of dark matter production, the freeze-in mechanism for the two-step case. We show that the freeze-in mechanism is modified by the temporary vacuum expectation value of the inert scalar field. In both cases, the first-order phase transitions could produce observable gravitational wave spectra. In particular for the one-step phase transition, the generated gravitational waves with sizable energy density are intrinsically correlated with the dark matter production mechanism, and can be detectable by future space-based interferometers. [ABSTRACT FROM AUTHOR]

High-energy standard model (SM) particles in the early Universe are generated by the decay of heavy long-lived particles. The subsequent thermalization occurs through the splitting of high-energy primary particles into lower-energy daughters in primordial thermal plasma. The principal example of such processes is reheating after inflation caused by the decay of inflatons into SM particles. Understanding of the thermalization at reheating is extremely important as it reveals the origin of the hot Universe, and could open up new mechanisms for generating dark matter and/or baryon asymmetry. In this paper, we investigate the thermalization of high-energy SM particles in thermal plasma, taking into account the Landau-Pomeranchuk-Migdal effect in the leading-log approximation. The whole SM particle content and all the relevant SM interactions are included for the first time, i.e., the full gauge interactions of SU(3)c×SU(2)L×U(1)Y and the top Yukawa interaction. The distribution function of each SM species is computed both numerically and analytically. We have analytically obtained the distribution function of each SM species after the first few splittings. Furthermore, we demonstrate that, after a sufficient number of splittings, the particle distributions are asymptotic to certain values at low momentum, independent of the high-energy particles injected by inflaton decay. The results are useful to calculate the DM abundance produced during the pre-thermal phase. An example is provided to illustrate a way to calculate the DM abundance from the scattering between the thermal plasma and high-energy particles in the cascade. [ABSTRACT FROM AUTHOR]

Coal spontaneous combustion (CSC) is a global, long-standing thermal hazard in coal mining that causes serious environmental damage, particularly in developing countries. Ionic liquids (ILs) are environmentally friendly, green, economical, and a new type of fire-preventing material that inhibits coal oxidation and alleviates thermal production. In this study, 1-butyl-3-methyl imidazole tetrafluoroborate ([BMIM][BF4]) and 1-butyl-3-methyl imidazole ([BMIM][I]) at various mass ratios (0.0, 0.5, 2.0, 5.0, and 10.0 mass%) were used to treat three types of coal (lignite, 1/3 coking coal, and anthracite) for CSC. The combustion-mass loss and thermal release rate of ILs treated relative to untreated coal samples were investigated using a synchronous thermal analyzer, and the optimal addition mass ratio of ILs was predicted. Not only do ILs have the most efficient inhibiting effect, but they also consider the economic benefit. Per thermogravimetric-differential scanning calorimetry, for the content of 5.0 mass% [BMIM][BF4], the inhibiting effect is favorable for universal applications. In addition, coal samples treated with 5.0 mass% [BMIM][BF4] were subjected to programmed-temperature heating experiment testing. The oxygen consumption rate, inhibiting effect, as well as apparent activation energy, were determined. The inhibiting effect at 120.0–150.0 °C was the most obvious, which provided the basis of the application for CSC prevention. [ABSTRACT FROM AUTHOR]

The purpose of this study is to fabricate highly dispersed powder suitable for spheroidization with further application in additive technologies. The volumetric reduction of the FeCl2–CaCl2 melt by calcium dissolved in CaCl2 produced a fine iron powder. The process included three states, notably, the preparation of melts containing FeCl2 and Ca, their mixing, and high-temperature aging at 800°C for 1 h. Upon finishing the process, the solidified fusion cake is divided into top and bottom parts. The product from the top part has a specific surface of 7.60 m2/g, and that from the bottom part has a specific surface of 5.38 m2/g. The average particle size is 157 μm for the former and 124 μm for the latter. Ultrasonic dispersing is reduced to 26 μm and 71 μm, respectively. Quantitative X-ray phase analysis shows that the main phase of powder is metallic iron (more than 97 wt %). Thus, the originality of the research is due to the application of an intense volumetric reduction of iron from chloride melts by calcium dissolved in its chloride. The uniqueness of the study is due to its product, so far as the main part of reduced iron is arranged in the melt bulk in the form of linear aggregates 40–600 μm in length and 10–50 μm in diameter, which easily destruct by ultrasonic dispersal into separate crystals with an average size of 26 μm. The results of the study show the possibility of implementing the calcium-thermal production of fine iron powder. [ABSTRACT FROM AUTHOR]

The experience of modification of ore-thermal production is described. A rectangular furnace is replaced by a round ore-thermal furnace at a retained power supply, namely, a three-phase furnace transformer with star-connected terminals. Unique design solutions are proposed to achieve the maximum possible level of introduced useful power and the minimum inductive reactance of the secondary current lead. [ABSTRACT FROM AUTHOR]