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Abstract The present paper describes an experimental study on mechanical properties of additively manufactured anti-tetrachiral auxetic structures under shear and flexural loading. Specimens of ABS material are fabricated using material [...]

Gas flotation for oily wastewater treatment is based on the attachment of gas bubbles to oil droplets to produce lighter aggregates that rise to the wastewater surface. It is a feasible, promising, and effective method for oily wastewater treatment due to its high separation efficiency with no secondary contamination, cost-effectiveness, and simple operation. This review focuses on separating oil from emulsions by gas flotation using microbubbles (MBs) and nanobubbles (NBs), which offer the advantages of small bubble size, large specific surface area, and slow rising velocity. The properties of different types of gas bubbles and their generation methods were discussed. Different gas flotation system designs and operational parameters were summarized for dissolved gas flotation, induced gas flotation, and electrolytic flotation (EF). The review illustrated that oil removal efficiency in MB- and NB-based gas flotation was affected by various factors including initial oil concentration, pH, temperature, flotation time, and oil droplet size. Key words: gas flotation, microbubble, nanobubble, oil-in-water emulsion, oily wastewater treatment La flottation gazeuse pour le traitement des eaux usées contaminées par les hydrocarbures est basée sur la fixation des bulles de gaz aux gouttelettes d'hydrocarbures pour produire des agrégats plus légers qui remontent àla surface des eaux usées. Il s'agit d'une méthode réalisable, prometteuse et efficace pour le traitement des eaux usées contaminées par les hydrocarbures en raison de sa grande efficacité de séparation sans contamination secondaire, de sa rentabilité et de sa simplicité d'utilisation. Cette synthèse se concentre sur la séparation des hydrocarbures des émulsions par flottation gazeuse en utilisant des microbulles et des nanobulles qui offrent les avantages d'une petite taille de bulle, d'une grande surface spécifique et d'une vitesse d'ascension lente. Les propriétés des différents types de bulles de gaz et leurs méthodes de génération ont été discutées. Les différentes conceptions de systèmes de flottation gazeuse et les paramètres opérationnels ont été résumés pour la flottation par gaz dissous, la flottation par gaz induit et la flottation électrolytique. La synthèse a montré que l'efficacité de l'élimination des hydrocarbures par la flottation gazeuse àbase de microbulles et de nanobulles était affectée par divers facteurs, notamment la concentration initiale d'hydrocarbures, le pH, la température, le temps de flottation et la taille des gouttelettes d'hydrocarbures. [Traduit par la Rédaction] Mots-clés : flottation gazeuse, microbulles, nanobulles, émulsion d'huile dans l'eau, traitement des eaux usées contaminées aux hydrocarbures, 1 Introduction Oily wastewater is generated from oil spill incidents and many other sources, such as food processing, oil refining, textile and leather industries, metal rolling and finishing, paper deinking, [...]

In the present work, an experimental investigation is performed to study the influence of process parameters on mechanical properties of tetra-anti-chiral auxetic structures manufactured by material extrusion (ME) technique of additive manufacturing (AM). Process parameters namely layer height, print speed, and print temperature are considered, while responses are compressive strength ([sigma]), modulus (E), and specific energy absorption (SEA). Specimens of acrylonitrile-butadiene-styrene (ABS) polymer are fabricated and then tested under compressive loading. From the experimental results, it is observed that all process parameters significantly influence the mechanical properties of the structure. Scanning electron microscope (SEM) is used to study microstructural defects of the tested specimen. To maximize the responses, optimization of process parameter is performed using desirability function approach. Regressive models are developed to predict the mechanical properties. KEYWORDS additive manufacturing, chiral, compression, mechanical properties, modulus, strength, 1 | INTRODUCTION Cellular materials are used in lightweight sandwich panels, which have wide industrial applications due to high stiflhess-to-weight ratio and impact energy absorption. [1] Metamaterials, also known as [...]