Unified theoretical framework for temperature regulation via phase transition.

Heating-Induced Phase Transition of Bupropion Hydrobromide Polymorphs

When the size of the material reaches the nanometer level, due to surface effects and small size effects, the substances would cause great changes in chemical reaction equilibrium, reaction kinetics, phase transition, adsorption, electrochemistry and catalysis, and these changes are attributed to changes in their thermodynamic properties. Particle size and morphology are the main factors affecting the thermodynamic properties of nanomaterials, while molar enthalpy and molar entropy are important thermodynamic properties of nanomaterials. The effects of particle size and morphology on molar entropy and molar enthalpy in phase transitions (including melting and sublimation), electrochemistry and adsorption are described in this paper.

To identify the low energy pathway for solid-to-solid phase transition has been a great challenge in physics and material science. This work develops a new theoretical method, namely, variable-cell double-ended surface walking (VC-DESW) to locate the transition state (TS) and deduce the pathway in solid phase transition. Inherited from the DESW method ( J. Chem. Theory Comput. 2013 , 9 , 5745 ) for molecular systems, the VC-DESW method implements an efficient mechanism to couple the lattice and atom degrees of freedom. The method features with fast pseudopathway building and accurate TS location for solid phase transition systems without requiring expensive Hessian computation and iterative pathway optimization. A generalized coordinate, consisting of the lattice vectors and the scaled atomic coordinates, is designed for describing the crystal potential energy surface (PES), which is able to capture the anisotropic behavior in phase transition. By comparing with the existing method for solid phase transition in different systems, we show that the VC-DESW method can be much more efficient for finding the TS in crystal phase transition. With the combination of the recently developed unbiased stochastic surface walking pathway sampling method, the VC-DESW is further utilized to resolve the lowest energy pathway of SiO2 α-quartz to quartz-II phase transition from many likely reaction pathways. These new methods provide a powerful platform for understanding and predicting the solid phase transition mechanism and kinetics.

The unified power quality conditioner (UPQC) is an effective solution for addressing power quality issues in modern power systems, with its ability to regulate both voltage and current. However, existing UPQC operational strategies lack sufficient adaptability and flexibility in managing load-side phase, especially when dealing with complex grid disturbances. This paper proposes a unified framework for adaptive and flexible phase angle regulation, primarily based on two novel algorithms: the practical optimized-VA-loading operational strategy (POOS) and the universal flexible control method (UFCM). Firstly, the proposed POOS method, utilizing phase angle control, enables online VA loading optimization within the UPQC's safe operating range according to real-time grid conditions. A comprehensive discussion of the method is presented, including the working principles, operational boundaries, and iterative computation process. Secondly, the proposed UFCM ensures smooth phase control of the load voltage throughout complex grid events. A dual-speed phase-locked loop is introduced to decouple the target and real-time phase, with parameter design guidelines and a discretization process provided. Furthermore, the unified framework is thoroughly explained, which balances the steady-state optimization requirements of the UPQC with the dynamic load-side power quality. Finally, experimental results validate the effectiveness of the unified framework under complex grid disturbance scenarios.

A synthesised review of pandemic-driven consumer behaviours and applied theories: Towards a unified framework

Based on the experimental observation that there is a coexisting region between the antiferromagnetic (AF) and d-wave superconducting (dSC) phases, the influences of gauge boson mass m a on chiral symmetry restoration and deconfinement phase transitions in QED3 are investigated simultaneously within a unified framework, i.e., Dyson–Schwinger equations. The results show that the chiral symmetry restoration phase transition in the presence of the gauge boson mass m a is a typical second-order phase transition; the chiral symmetry restoration and deconfinement phase transitions are coincident; the critical number of fermion flavors N c f decreases as the gauge boson mass m a increases, which implies that there exists a boundary that separates the N c f –m a plane into chiral symmetry breaking/confinement region for (N c f , m a ) below the boundary and chiral symmetry restoration/deconfinement region for (N c f , m a ) above it.

Black holes, traditionally studied as solutions of Einstein's equations, exhibit rich thermodynamic behavior, including well-defined phase transitions. In this work, we establish a unified topological framework to describe various black hole phase transitions, including Davies-type and extremal phase transitions. Our approach reveals a deeper underlying structure in black hole thermodynamics, demonstrating that these seemingly distinct transitions can be connected through topology. Furthermore, we show that the classification of phase transitions can be enriched by the introduction of non-zero topological charges, offering a novel perspective beyond conventional thermodynamic analysis. These findings not only strengthen the thermodynamic interpretation of black holes but also open new avenues for exploring phase transitions in gravitational systems from a topological standpoint.

Analysis of trends in phase change enthalpy, entropy and temperature for alkanes, alcohols and fatty acids

Phase transitions are a common phenomenon in condensed matter and act as a critical degree of freedom that can be employed to tailor the mechanical or electronic properties of materials. Understanding the fundamental mechanisms of the thermodynamics and kinetics of phase transitions is, thus, at the core of modern materials design. Conventionally, studies of phase transitions have, to a large extent, focused on pristine bulk phases. However, realistic materials exist in a complex form; their microstructures consist of different point and extended defects. The presence of defects impacts the thermodynamics and kinetics of phase transitions, but has been commonly ignored or treated separately. In recent years, with the significant advances in theoretical and experimental techniques, there has been an increasing research interest in modeling and characterizing how defects impact or even dictate phase transitions. The present review systematically discusses the recent progress in understanding the kinetics of defect-characterized phase transitions, derives the key mechanisms underlying these phase transitions, and envisions the remaining challenges and fruitful research directions. We hope that these discussions and insights will help to inspire future research and development in the field.

Investigation of thermodynamic state evolution, phase transition and mixing of the hydrocarbon droplet in convective supercritical environments

Nigeria is one of the developing countries with a very weak and incomprehensive regulatory framework for clinical trials. Past abuses of human subjects in clinical trials and cases of negligence and outright fraud necessitate the need for a stronger legal framework. An outbreak of meningitis in Nigeria in 1996 led to clinical trial of Trovan Drugs by Pfizer, which left many of the research subjects seriously impaired. Some died while some suffered paralysis and brain damage. It was obvious Nigeria has a weak regulatory frame work from the incident that took place in the mentioned above at the Infectious Dieses Hospital (IDH) Kano. Available literatures have also shown that at the time of the trial in Kano, there was no ethics committee to ensure ethics review process and monitor the ongoing trial. Objectives: This research aimed at examining the Nigerian regulatory framework to bring out its weaknesses. It will also examine the strength and weakness of the current regulatory agencies, and suggest better regulatory framework that will make Nigerians less vulnerable to manipulation and fraud in clinical trials. Methodology: Library research is used to study both primary and secondary legal resources. Finding: Lack of standard regulatory body and lack unified legal framework is the cause of failure to protect human subject in Nigeria.

Cold storage systems are essential for ensuring the quality and safety of temperature-sensitive goods across industries such as food, pharmaceuticals, and biotechnology. However, traditional temperature regulation approaches often struggle with delayed fault detection, lack of adaptive response mechanisms, and inefficient energy consumption. As modern supply chains grow increasingly complex, the demand for intelligent, automated cold storage solutions has become more urgent. This paper proposes a comprehensive data-driven framework for intelligent cold storage monitoring and temperature regulation. By integrating Internet of Things (IoT) sensors, real-time data acquisition, machine learning (ML) algorithms, and predictive control models, the system continuously tracks environmental and equipment metrics. Anomaly detection techniques are used to identify deviations from normal behavior, while reinforcement learning is applied to optimize response strategies in varying operational contexts. The framework includes a cloud-based data processing layer, an ML-based anomaly detection engine, and a closed-loop control module capable of adjusting temperature settings proactively. Through simulations and real-world deployment scenarios, the system demonstrated improved temperature stability, faster fault diagnosis, and reduced energy consumption compared to conventional control mechanisms. The findings suggest that combining ML and IoT technologies provides a scalable and adaptive solution for next-generation cold storage management.

SummaryWe consider the problem of testing functional constraints in a class of functional concurrent linear models where both the predictors and the response are functional data measured at discrete time points. We propose test procedures based on the empirical likelihood with bias-corrected estimating equations to conduct both pointwise and simultaneous inferences. The asymptotic distributions of the test statistics are derived under the null and local alternative hypotheses, where sparse and dense functional data are considered in a unified framework. We find a phase transition in the asymptotic null distributions and the orders of detectable alternatives from sparse to dense functional data. Specifically, the tests proposed can detect alternatives of √n-order when the number of repeated measurements per curve is of an order larger than nη0 with n being the number of curves. The transition points η0 for pointwise and simultaneous tests are different and both are smaller than the transition point in the estimation problem. Simulation studies and real data analyses are conducted to demonstrate the methods proposed.

We develop a simple Ginsburg-Landau theory to study all the possible phases and phase transitions in 4He, analyze the condition for the existence of the supersolid (SS) and map out its global phase diagram from a unified framework. If the condition favors the existence of the SS, we use the GL theory to address several experimental facts and also make some predictions that are amenable to experimental tests. A key prediction is that the x-ray scattering intensity from the SS ought to have an additional modulation over that of the normal solid. The modulation amplitude is proportional to the nonclassical rotational-inertial observed in the torsional oscillator experiments.

Describes a system for accurate specific heat measurements of solid samples with masses of the order of 10-6 kg with automatic stepwise temperature regulation and data read-out in the range from 2-380K and with the ability to apply a uniaxial pressure using an AC technique. The system has great flexibility in temperature regulation and selection of frequency of heating. The temperature steps can be varied from 1 mK to 1K. The time intervals between successive measurements may be from a few seconds to several hours. In particular, the system is well suited for measurements at solid-state phase transitions and has been tested largely in this connection. Uniaxial pressure up to 108 Pa has been applied. The absolute accuracy of specific heat measurements is about +or-5%, but the relative accuracy is typically 0.1%. Since the system is intended for the study of phase transitions, the latter number is of greater importance.