Crystallization Kinetics in BaTiO3 Synthesis from Hydrate Precursors via Microwave-Assisted Heat Treatment

The crystallization kinetics in BaTiO3 synthesis from hydrate precursors via microwave-assisted heating (MWH) were investigated. The structural and chemical features of powders synthesized via MWH and conventional heating (CH) were compared. The charged radicals generated under microwave irradiation were identified by chemical analysis and real-time charge flux measurements. Using Ba(OH)2∙H2O (BH1), Ba(OH)2 (BH0), and BaCO3 (BC) as the precursors for a Ba source, and TiO2∙4H2O (TH) for a Ti source, three different mixture samples, BH1TH (BH1 + TH), BH0TH (BH0 + TH), and BCTH (BC + TH), were heat-treated in the temperature range of 100–900 °C. BaTiO3 powders were synthesized at temperatures as low as 100 °C when sample BH1TH was subjected to MWH. Based on the growth exponent (n), the synthesis reactions were inferred to be diffusion-controlled processes (3 ≤ n ≤ 4) for MWH and interface-controlled processes (2 ≤ n ≤ 3) for CH. Current densities of approximately 0.073 and 0.022 mA/m2 were measured for samples BH1TH and BH0TH, respectively, indicating the generation of charged radicals by the interaction between the precursors and injected microwaves. The radicals were determined as OH− groups by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.

Variability as normal as apple pie

In recent studies in second language (L2) development, notably within the focus of Complex Dynamic Systems Theory (CDST), non-systematic variation has been extensively studied as intra-individual variation, which we will refer to as variability. This paper argues that variability is functional and is needed for development. With examples of four longitudinal case studies we hope to show that variability over time provides valuable information about the process of development. Phases of increased variability in linguistic constructions are often a sign that the learner is trying out different constructions, and as such variability can be evidence for change, and change can be learning. Also, a limited degree of variability is inherent in automatic or controlled processes. Conversely, the absence of variability is likely to show that no learning is going on or the system is frozen.

Biochar—just a black matter is not enough

What differs biochar from charcoal? The simple answer is that biochar is a carbon-rich product obtained from the thermal decomposition of organic material, at the presence of no or only a bit of oxygen. In principle, the production of biochar is comparable to the production of charcoal, one of the oldest and most established processes developed by mankind. While charcoal is made traditionally from wood, biochar can be based on a wide range of biomass and biomass residues. However, a variety of technologies for the production of biochar has been developed in recent years. The technologies are based on pyrolysis, gasification, or hydrothermal carbonization and are ranging from simple units, like heated steel drums to full automated and controlled processes. Therefore, the obtained products have tremendous differences in its properties and resulting qualities. The quality defines the field of application. To obtain the required quality for each application, the right process must be applied. Consequently, it is not enough only to enrich the carbon content by thermal decomposition of organic material. The production of tailor-made biochar for specific high added–value application is much more complex. In addition, side products like liquid biofuels make business cases stronger. If it is done in the right way, biochar production combined with advanced biofuels can be an economic solution to overcome the problems of climate change. “So for the future of mankind, this black matter might give the light at the end of the tunnel.”

ON APPROXIMATE OPTIMAL CONTROL FOR THE REACTION-DIFFUSION PROCESS IN MICROINHOMOGENEOUS MEDIUM

The problem of constructing an approximate optimal control for controlled processes of chemical kinetics in microinhomogeneous medium is considered. Such processes are described by semilinear parabolic equations of the reaction-diffusion type with coefficients of the form . The preference of an approximate control as the optimal control in the problem with averaged coefficients is justified. An example of the construction of such a control is discussed and its efficiency is demonstrated.

Generalized solutions of optimal control problems

The problems of optimal control of systems of algebraic-integro-differential equations and partial differential equations are considered, which describe controlled processes with concentrated and distributed parameters. Generalized optimal solutions that exist for a wide range of optimal control applications are identified. Methods for constructing approximate generalized solutions are considered.

Habit and Skill in the Domain of Joint Action

Dichotomous thinking about mental phenomena is abundant in philosophy. One particularly tenacious dichotomy is between “automatic” and “controlled” processes. In this characterization automatic and unintelligent go hand in hand, as do non-automatic and intelligent. Accounts of skillful action have problematized this dichotomous conceptualization and moved towards a more nuanced understanding of human agency. This binary thinking is, however, still abundant in the philosophy of joint action. Habits and skills allow us agentic ways of guiding complex action routines that would otherwise overwhelm our reflective capacities. In this paper, I look at how theories of skill, habit, and know-how in individual action can inform a non-dichotomous account of joint action. I argue that a fuller understanding of joint agency has to understand not only group know-how, but also the role of attention and the highly integrated types of control that allow agents to act together.

rethinking_neuroaesthetics

To date, neuroaesthetics research has primarily framed aesthetic experiences as a special case of cognition. In the current paper, we argue that the dominance of this specialised approach needs rethinking. Instead, we propose a generalised framework that is inspired by the semantic cognition literature and that treats aesthetic experience as just one way to gain meaning from the environment, rather than as a special case. According to our framework, aesthetic experiences are underpinned by the same cognitive and brain systems that are involved in deriving meaning from the environment in general, such as modality-specific conceptual representations and controlled processes for retrieving the appropriate type of information. By embracing broader and more mature fields of research within cognitive neuroscience, our generalised semantic cognition view of aesthetic experience has substantial implications for theory development; it leads to novel, falsifiable predictions and it reconfigures a central debate by forcing researchers to assess foundational assumptions regarding the specificity of systems that may be involved in aesthetic experiences.