Clay as a Sustainable Binder for Concrete—A Review

The negative environmental impacts of Portland cement as a binder in the construction industry have created a growing impetus to develop sustainable alternative binders. Various types of clay have been considered as potential cement replacements. The impact of clays as cement replacement depends on the dosage and treatment methods. This paper presents a comprehensive review to determine the effects of different types of clay on the fresh and hardened properties of concrete mixtures by analyzing the experimental database reported by the literature, including raw, calcined, modified, nano, and organo. This study intends to show the process of optimizing the use of clay in concrete, the reason behind converting raw clay to modified types, and research gaps through a comparison study between different types of clays. The present review study shows that clay-based concrete mixtures have higher thixotropy and yield stress values, improving shape stability. This results in lower early-age shrinkage of the concrete. However, the high floc strength of clay-based concrete causes a reduction in flowability. Treatment methods of raw clay, such as calcination and nano-sized clay particles, improve concrete compressive strength. General results of the previous studies highlight that all types of clay investigated positively affect the resistance of concrete to environmental attack.

Phase field modeling for the morphological and microstructural evolution of metallic materials under environmental attack

The complex degradation of metallic materials in aggressive environments can result in morphological and microstructural changes. The phase-field (PF) method is an effective computational approach to understanding and predicting the morphology, phase change and/or transformation of materials. PF models are based on conserved and non-conserved field variables that represent each phase as a function of space and time coupled with time-dependent equations that describe the mechanisms. This report summarizes progress in the PF modeling of degradation of metallic materials in aqueous corrosion, hydrogen-assisted cracking, high-temperature metal oxidation in the gas phase and porous structure evolution with insights to future applications.

The Role of IL-35 in the Pathophysiological Processes of Liver Disease

It is known that liver diseases have several characteristics of massive lipid accumulation and lipid metabolic disorder, and are divided into liver inflammation, liver fibrosis, liver cirrhosis (LC), and hepatocellular carcinoma (HCC) in patients. Interleukin (IL)-35, a new-discovered cytokine, can protect the liver from the environmental attack by increasing the ratio of Tregs (T regulatory cells) which can increase the anti-inflammatory cytokines and inhibit the proliferation of immune cellular. Interestingly, two opposite mechanisms (pro-inflammatory and anti-inflammatory) have connection with the ultimate formation of liver diseases, which suggest that IL-35 may play crucial function in the process of liver diseases through immunosuppressive regulation. Besides, some obvious advantages also imply that IL-35 can be considered as a new therapeutic target to control the progression of liver diseases, while its mechanism of function still needs further research.

Nanotechnology in Food Systems: A Review

Recent developments of nanotechnology find its way into various fields of food production in our days. Nanotechnology could offer benefits in development of food products with enhanced functionality for health promotion, or modified texture convenient for elderly, and in quality and safety issues in the food supply chain. Nanoencapsulated bioactive components such as vitamins, antibacterial agents contribute to production of enriched food stuffs with the required appearance, flavour, taste, and texture. Nanomaterials can protect the sensitive compounds from environmental attack, release them in a programmed way, and provide favourable improvement in the bioavailability of nutraceuticals. The innovative approach in food packaging, including the detection, indication, and control of food products, serves the quality and safety improvements.

Mechanical Properties of 3D-Printed Maraging Steel Induced by Environmental Exposure

Changes in the mechanical properties of selective laser melted maraging steel 300 induced by exposure to a simulated marine environment were investigated. Maraging steel samples were printed in three orientations: vertical (V), 45° (45), and horizontal (H) relative to the print bed. These were tested as-printed or after heat-treatment (490 °C, 600 °C, or 900 °C). One set of specimens were exposed in a salt spray chamber for 500 h and then compared to unexposed samples. Environmental attack induced changes in the microstructural features and composition were analyzed by scanning electron microscopy and energy dispersive spectroscopy respectively. Samples printed in the H and 45° directions exhibited higher tensile strength than those printed in the V direction. Corrosion induced reduction in strength and hardness was more severe in specimens heat-treated between 480 °C and 600 °C versus as-printed samples. The greatest decrease in tensile strength was observed for the 45°-printed heat-treated samples after exposure. A comparison between additive and subtractive manufactured maraging steel is presented.

Failure Mechanism of Yttria Stabilized Zirconia Atmospheric Plasma Sprayed Thermal Barrier Coatings Subjected to Calcia-Magnesia-Alumino-Silicate Environmental Attack

The contribution focuses on the description of failure mechanism of atmospheric plasma sprayed multilayer thermal barrier coatings subjected to calcia-magnesia-alumino-silicate (CMAS) environmental attack. To identify exothermic and endothermic reactions which occurred during heating/cooling by means of calorimetry was also utilized initial yttria stabilized zirconia (YSZ) powder subsequently used for thermal spraying of multilayer thermal barrier coating system (TBCs), CMAS powder later on utilized for thin layer deposition and its mixture. Atmospheric plasma spray technique was used to produce the TBCs on a grit blasted nickel-based superalloy substrates, where CoNiCrAlY powder was used for deposition of a bond coat and YSZ powder was sprayed as a top coat. In accordance to the aerospace standard the thin layer of CMAS was deposited on as sprayed TBCs samples surface from its colloidal solution by paint brush method. Burner-rig test, utilizing direct propane-oxygen flame, was used for thermal cyclic exposition of the multilayer coated samples at the temperature of 1150 °C. Samples after thermal cyclic exposure test were investigated by means of materialographic analysis approaches. The significant reduction in life-time of CMAS coated YSZ top coat was observed due to lower melting point phase formation and molten silicate crystallization within the pores providing the spallation identified as a major mechanism of TBCs failure.

Design of Massive Casting Controlling Early Age Properties of Concrete

The design of concrete structures exposed to environmental attack requires serious attention for concrete durability. Early age cracking due to autogenous deformations should be avoided.In this work the study of the structural effects of hydration heat and rheological behaviour of a massive concrete casting is presented. The object of the study is a skyscraper foundation slab. Aim of the work is the numerical simulation of what occurs to the structure during the hardening, in order to avoid unforeseen autogenous cracking and therefore the choice of a tailor-made concrete mixture able to fulfil the performance criteria.Non-linear finite element coupled thermal and mechanical analyses have been performed taking into account: hydration heat generation and dispersion, dimension and sequence of the casting, evolution of concrete mechanical properties in time during the hardening reaction, creep and differential shrinkage.

A vueltas con El Algarrobico: la historia interminable de un despropósito medioambiental

LABURPENA: Lan honetan, El Algarrobico hotelaren inguruan jarraitutako ibilbide judizialaren balorazioa egiten da; Cabo de Gata-Níjar Parke Naturalean dago hotela (Almerian), eta ibilbide hori azkenean ingurumenaren aurkako atentatu bihurtu dela esan liteke. Izan ere, Andaluziako Justizia Auzitegi Nagusiaren azken bi epaiek —2014koak— guztiz irauli dute higiezina eraistera bideratuta zegoela zirudien prozesua, urbanizagarritzat jotzen baitute eraikina kokatuta dagoen lurzorua, eta legezkotzat jotzen baitute bere garaian emandako lizentzia. RESUMEN: En el presente trabajo se lleva a cabo una valoración del itinerario judicial seguido en relación con el hotel El Algarrobico, situado en el Parque Natural de Cabo de Gata-Níjar (Almería) y que ha acabado convirtiéndose en lo que podía denominarse un atentado medioambiental. Las dos últimas sentencias, de 2014, del Tribunal Superior de Justicia de Andalucía han dado un vuelco radical a un proceso que parecía estar abocado a la demolición del inmueble puesto que califican como urbanizable el suelo en el que éste fue construido y consideran legal la licencia otorgada en su día. ABSTRACT: This work deals with an assessment of the judicial path of the Hotel El Algarrobico, located in the Natural Park of Cabo de Gata-Níjar (Almería) and that it has became what it could be called a environmental attack. Last two judgments, from 2014, by the High Court of Justice of Andalucía have changed drastically the process that seemed to be committed to the demolition of the building since they qualify the land where it was built as developable and they consider the permit granted in the past legal.