High-throughput screening of the thermoelastic properties of ultrahigh-temperature ceramics

Ultrahigh-temperature ceramics (UHTCs) are a group of materials with high technological interest because of their applications in extreme environments. However, their characterization at high temperatures represents the main obstacle for their fast development. Obstacles are found from an experimental point of view, where only few laboratories around the world have the resources to test these materials under extreme conditions, and also from a theoretical point of view, where actual methods are expensive and difficult to apply to large sets of materials. Here, a new theoretical high-throughput framework for the prediction of the thermoelastic properties of materials is introduced. This approach can be systematically applied to any kind of crystalline material, drastically reducing the computational cost of previous methodologies up to 80% approximately. This new approach combines Taylor expansion and density functional theory calculations to predict the vibrational free energy of any arbitrary strained configuration, which represents the bottleneck in other methods. Using this framework, elastic constants for UHTCs have been calculated in a wide range of temperatures with excellent agreement with experimental values, when available. Using the elastic constants as the starting point, other mechanical properties such a bulk modulus, shear modulus, or Poisson ratio have been also explored, including upper and lower limits for polycrystalline materials. Finally, this work goes beyond the isotropic mechanical properties and represents one of the most comprehensive and exhaustive studies of some of the most important UHTCs, charting their anisotropy and thermal and thermodynamical properties.Ministerio de Ciencia e Innovación PID2019-106871GB-I00European Union 752608Red Española de Supercomputación QS-2019-2-0006, QS-2019-3-0021, QS-2020-2-003

Spinodal superlattices of topological insulators

Spinodal decomposition is proposed for stabilizing self-assembled interfaces between topological insulators (TIs) by combining layers of iso-structural and iso-valent TlBi$X_2$ ($X$=S, Se, Te) materials. The composition range for gapless states is addressed concurrently to the study of thermodynamically driven boundaries. By tailoring composition, the TlBiS$_2$-TlBiTe$_2$ system might produce both spinodal superlattices and two dimensional eutectic microstructures, either concurrently or separately. The dimensions and topological nature of the metallic channels are determined by following the spatial distribution of the charge density and the spin-texture. The results validate the proof of concept for obtaining spontaneously forming two-dimensional TI-conducting channels embedded into three-dimensional insulating environments without any vacuum interfaces. Since spinodal decomposition is a controllable kinetic phenomenon, its leverage could become the long-sought enabler for effective TI technological deployment.Comment: 11 pages, 4 figure

PalmSpace : leveraging the palm for touchless interaction on public touch screen devices

The touchscreen is the primary solution to interact with public devices such as Automated Teller Machines (ATMs). However, the touch modality raises health concerns since users have to touch the screens, and therefore risk the spread of contagious diseases. I designed PalmSpace, an alternate input technique leveraging users’ hand palms to interact with public devices. With PalmSpace, UI elements are mapped onto the users’ palms and can be accessed by touching various locations directly on the palm. I conducted a series of user studies to evaluate several design options, such as interface layout, item size, preferred item location, and suitable feedback for items. Based on the results, I designed PalmSpace and compared its performance with mid-air input. I showed that PalmSpace is a potential solution to interact with public devices without using their touchscreen. I concluded with design guidelines for using the palm as an alternative input space for touchscreen devices.Science, Irving K. Barber Faculty of (Okanagan)Computer Science, Mathematics, Physics and Statistics, Department of (Okanagan)Graduat

Vanadium-catalyzed selective oxidation of alcohols to aldehydes and ketones with tert-butyl hydroperoxide

The oxidation of alcohols to aldehydes and ketones has been described using silica-supported vanadium(IV) oxide (V/SiO<SUB>2</SUB>, 1) in the presence of tert-butyl hydroperoxide in tert-butyl alcohol at ambient temperature with quantitative yields. The procedure is simple, efficient and environmentally benign

A Comprehensive Review of Food Hydrogels: Principles, Formation Mechanisms, Microstructure, and Its Applications

Food hydrogels are effective materials of great interest to scientists because they are safe and beneficial to the environment. Hydrogels are widely used in the food industry due to their three-dimensional crosslinked networks. They have also attracted a considerable amount of attention because they can be used in many different ways in the food industry, for example, as fat replacers, target delivery vehicles, encapsulating agents, etc. Gels—particularly proteins and polysaccharides—have attracted the attention of food scientists due to their excellent biocompatibility, biodegradability, nutritional properties, and edibility. Thus, this review is focused on the nutritional importance, microstructure, mechanical characteristics, and food hydrogel applications of gels. This review also focuses on the structural configuration of hydrogels, which implies future potential applications in the food industry. The findings of this review confirm the application of different plant- and animal-based polysaccharide and protein sources as gelling agents. Gel network structure is improved by incorporating polysaccharides for encapsulation of bioactive compounds. Different hydrogel-based formulations are widely used for the encapsulation of bioactive compounds, food texture perception, risk monitoring, and food packaging applications

Recent Advances in Cellulose-Based Hydrogels: Food Applications

In the past couple of years, cellulose has attracted a significant amount of attention and research interest due to the fact that it is the most abundant and renewable source of hydrogels. With increasing environmental issues and an emerging demand, researchers around the world are focusing on naturally produced hydrogels in particular due to their biocompatibility, biodegradability, and abundance. Hydrogels are three-dimensional (3D) networks created by chemically or physically crosslinking linear (or branching) hydrophilic polymer molecules. Hydrogels have a high capacity to absorb water and biological fluids. Although hydrogels have been widely used in food applications, the majority of them are not biodegradable. Because of their functional characteristics, cellulose-based hydrogels (CBHs) are currently utilized as an important factor for different aspects in the food industry. Cellulose-based hydrogels have been extensively studied in the fields of food packaging, functional food, food safety, and drug delivery due to their structural interchangeability and stimuli-responsive properties. This article addresses the sources of CBHs, types of cellulose, and preparation methods of the hydrogel as well as the most recent developments and uses of cellulose-based hydrogels in the food processing sector. In addition, information regarding the improvement of edible and functional CBHs was discussed, along with potential research opportunities and possibilities. Finally, CBHs could be effectively used in the industry of food processing for the aforementioned reasons

Valorization of Food Waste as Animal Feed: A Step towards Sustainable Food Waste Management and Circular Bioeconomy

The growing population and healthy food demands have led to a rise in food waste generation, causing severe environmental and economic impacts. However, food waste (FW) can be converted into sustainable animal feed, reducing waste disposal and providing an alternative protein source for animals. The utilization of FW as animal feed presents a solution that not only tackles challenges pertaining to FW management and food security but also lessens the demand for the development of traditional feed, which is an endeavour that is both resource and environmentally intensive in nature. Moreover, this approach can also contribute to the circular economy by creating a closed-loop system that reduces the use of natural resources and minimizes environmental pollution. Therefore, this review discusses the characteristics and types of FW, as well as advanced treatment methods that can be used to recycle FW into high-quality animal feed and its limitations, as well as the benefits and drawbacks of using FW as animal feed. Finally, the review concludes that utilization of FW as animal feed can provide a sustainable solution for FW management, food security, preserving resources, reducing environmental impacts, and contributing to the circular bioeconomy