Model development and prediction of anti-icing longevity of asphalt pavement with salt-storage additive

This study established a systematic simulation framework to predict the anti-icing longevity of a thin overlay of asphalt pavement with salt-storage additive (APSSA). The water and chloride transport in the overlay when subjected to varying precipitation, temperature, thermal cracking, and fatigue cracking over time were modeled using a Finite Element Method based software. The simulation included two parts: water transport followed by chloride transport. Water transport that obeys the law of conservation of mass was modeled using the phase transport in porous media (phtr) interface of COMSOL, while chloride transport based on Fick’s second law was modeled with the transport of diluted species (tds) interface. The simulation results show that the anti-icing function of a 16-mm thick overlay was fully effective in 2 years and 5 years for the minimum pavement temperature above -3.4 °C and -2.4 °C, respectively. These two pavement temperatures are equivalent to 97.4-percentile and 96.3-percentile of historical hourly pavement temperature near Pullman, Washington. Graphical abstract

Literature Review on the Pre-Slaughter Welfare of Italian Heavy Pigs

This work provides a narrative review of the available information on the welfare of Italian heavy pigs in the pre-slaughter phase (transport, lairage, and stunning). The meat from these pigs is used for specific PDO (Protected Designation of Origin) products, and the production rules for these specialties require higher body weight (160–170 kg) and age (in general more than 9 months) at slaughter than in most other countries. This may lead to specific behavioral and physiological needs of pigs. The present paper summarizes the main research findings and knowledge gaps for each of the pre-slaughter phases. Studies are presented according to the four principles of the Welfare Quality assessment protocol (good feeding, good housing, good health, and appropriate behavior). The results of the literature review indicate a lack of knowledge on several aspects. Most of studies were carried out in a single slaughterhouse, making it difficult to identify risk factors and confounding effects. Moreover, animal-based measures were assessed using different protocols, reducing the possibility of comparison across studies. These findings may serve as a basis for the development of specific research studies and policies aimed at enhancing the animal welfare level and the ethical attributes of this renowned production, also in accordance with consumers’ expectations.

System scan of the multiplicity correlation between forward and backward rapidities in the relativistic heavy-ion collisions by using a multi-phase transport model

A systematic study on forward-backward (FB) multiplicity correlations from large systems to small ones through a multi-phase transport model (AMPT) has been performed and the phenomenon that correlation strength increases with the centrality can be explained by taking the distribution of events as the superposition of a series of Gaussian distributions. It is also found that correlations in the η - Φ plane can imply the shape of event. Furthermore, long range correlations originate from the fluctuations associated with the source information. FB correlations allow us to decouple long range correlations from short range correlations, and may provide a chance to investigate the $\alpha$-clustering structure in initial colliding light nuclei as well. It seems the tetrahedron $^{16}$O + $^{16}$O collision gives a more uniform and symmetrical fireball, after that emits the final particles more isotropically or independently in the longitudinal direction, indicating that the forward-backward multiplicity correlation could be used to identify the pattern of $\alpha$-clustered $^{16}$O in future experiments.

Investigations of the linear and non-linear flow harmonics using the A Multi-Phase Transport model

The Multi-Phase Transport model (AMPT) is used to study the effects of the parton-scattering cross-sections ($\sigma_{pp}$) and hadronic re-scattering on the linear contributions to the flow harmonic \fourth, the non-linear response coefficients, and the correlations between different order flow symmetry planes in Au+Au collisions at 200~GeV. The model results, which agree with current experimental measurements, indicate that the higher-order flow harmonics are sensitive to the $\sigma_{pp}$ variations. However, the non-linear response coefficients and the correlations between different order flow symmetry planes are $\sigma_{pp}$ independent. These results suggest that further detailed experimental measurements which span a broad range of collision systems and beam energies could serve as an additional constraint for the theoretical models' calculations.

Further developments of a multi-phase transport model for relativistic nuclear collisions

A multi-phase transport (AMPT) model was constructed as a self-contained kinetic theory-based description of relativistic nuclear collisions as it contains four main components: the fluctuating initial condition, a parton cascade, hadronization, and a hadron cascade. Here, we review the main developments after the first public release of the AMPT source code in 2004 and the corresponding publication that described the physics details of the model at that time. We also discuss possible directions for future developments of the AMPT model to better study the properties of the dense matter created in relativistic collisions of small or large systems.

A Three-Phase Transport Model for High-Temperature Concrete Simulations Validated with X-ray CT Data

Concrete exposure to high temperatures induces thermo-hygral phenomena, causing water phase changes, buildup of pore pressure and vulnerability to spalling. In order to predict these phenomena under various conditions, a three-phase transport model is proposed. The model is validated on X-ray CT data up to 320 °C, showing good agreement of the temperature profiles and moisture changes. A dehydration description, traditionally derived from thermogravimetric analysis, was replaced by a formulation based on data from neutron radiography. In addition, treating porosity and dehydration evolution as independent processes, previous approaches do not fulfil the solid mass balance. As a consequence, a new formulation is proposed that introduces the porosity as an independent variable, ensuring the latter condition.