Search results

The present study spotlights the single and multicriteria decision-making (MCDM) methods to determine the optimal machining conditions and the predictive modeling for surface roughness (Ra) and cutting tool flank wear (VB) while hard turning of AISI 4340 steel (35 HRC) under dry environment.

In this study, Taguchi L16 design of experiments methodology was chosen. The experiments were performed under dry machining conditions using TiSiN-TiAlN nanolaminate PVD-coated cutting tool on which Taguchi and responses surface methodology (RSM) for single objective optimization and MCDM methods like the multi-objective optimization by ratio analysis (MOORA) were applied to attain optimal set of machining parameters. The predictive models for each response and multiresponse were developed using RSM-based regression analysis. S/N ratios, analysis of variance (ANOVA), Pareto diagram, Tukey's HSD test were carried out on experimental data for profound analysis.

Optimal set of machining parameters were obtained as cutting speed: at 180 m/min., feed rate: 0.05 mm/rev., and depth of cut: 0.15 mm; cutting speed: 145 m/min., feed rate: 0.20 mm/rev. and depth of cut: 0.1 mm for Ra and VB, respectively. ANOVA showed feed rate (96.97%) and cutting speed (58.9%) are dominant factors for Ra and VB, respectively. A remarkable improvement observed in Ra (64.05%) and VB (69.94%) after conducting confirmation tests. The results obtained through the MOORA method showed the optimal set of machining parameters (cutting speed = 180 m/min, feed rate = 0.15 mm/rev and depth of cut = 0.25 mm) for minimizing the Ra and VB.

This work contributes to realistic application for manufacturing industries those dealing with AISI 4340 steel of 35 HRC. The research contribution of present work including the predictive models will provide some useful guidelines in the field of manufacturing, in particular, manufacturing of gear shafts for power transmission, turbine shafts, fasteners, etc.

This review discusses the concept of edible nanocoatings (ENCs), the biomaterials used in the coating matrices, techniques of coating development, applications, challenges and safety regulations associated with nanotechnology in food products. These ENCs are capable of imparting increased shelf life, improved appearance, better physiological qualities and bioactive potentials such as antimicrobial and antioxidant properties. ENCs can be developed using the layer-by-layer method which forms multiple alternative layers adhered together primarily by electrostatic interactions.

Various keywords such as edible coatings (ECs), safety aspects and nanocoatings were used to search the literature from Google Scholar, Research Gate, ScienceDirect, Springer Link, Taylor and Francis and PubMed. After searching enough literature, 113 articles and research papers were examined, which provides the updated overview of different aspects of edible nano-coatings.

Consumers today are very much aware of the food quality and its safety. They demand food products with longer shelf life, which are minimally processed with natural or no preservatives. ECs based on biopolymers is an alternative technique, which is biodegradable and can be consumed as such without posing any safety risks. The emergence of nanotechnology in food processing has provided new insights to develop ECs at the nanoscale with improved mechanical and barrier properties

ECs are beneficial to consumers and to the environment. ECs have generated significant attention over years as an alternative to fossil-based plastics, considering their renewable and biodegradable features

This paper aims to update with information about edible coating on minimally processed and fresh fruits, focussing on the composition, active ingredients, antimicrobial concentration and their effect on ripening rate, phytonutrients retention and shelf-life of fruits. In future, the data will be helpful for the processors to select the best coating material and its effective concentration for different fresh and minimally processed fruits.

Major scientific information was collected from Scopus, Web of Science, Mendeley and Google Scholar. Several key words such as postharvest, edible coating, phytonutrients, shelf-life enhancement, bioactive compounds, minimally processed fruits and antimicrobial compounds were used to find the data. Relevant information was collected by using 90 recent research and review articles.

The main findings of this comprehensive review are to improve the quality of fruits, to meet the next-generation food security needs. However, in the process of achieving the goal of improving quality of food produce, embrace of synthetic, non-biodegradable packaging materials have increased, creating serious pollution problem. Amidst several alternatives for replacement of synthetic packaging, the option of biodegradable films and coatings showed promising results.

The paper represents recent information about the edible coating used for the enhancement of shelf-life of fresh and minimally processed fruits.

Nanotechnology as an emerging area if adequately harnessed could revolutionise food packaging and food processing industry worldwide. Although several benefits of nano-materials or particles in food packaging have been suggested, potential risks and health hazards of nano-materials or particles are possible as a result of migration of their particles into food materials. The purpose of this review therefore assessed nanotechnology and its applications in food packaging, consumer acceptability of nano-packaged foods and potential hazards and safety issues in nano-packaged foods.

This review takes a critical assessment of previous literature on nanotechnology and its impact on food packaging, consumer health and safety.

Applications of nanotechnology in food packaging could be divided into three main divisions: improved packaging, which involves mixing nano-materials into polymers matrix to improve temperature, humidity and gas barrier resistance of the packaging materials. Active packaging deals with direct interaction between nano-materials used for packaging and the food to protect it as anti-microbial or oxygen or ultra violet scavengers. Smart packaging could be used to sense biochemical or microbial changes in foods, as well as a tracker for food safety, to prevent food counterfeit and adulteration. The review also discussed bio-based food packaging which is biodegradable. Bio-based packaging could serve as veritable alternative to conventional packaging which is non-degradable plastic polymers which are not environmental friendly and could pose a threat to the environment. However, bio-based packaging could reduce material waste, elongate shelf life and enhance food quality. However, several challenges are envisaged in the use of nano-materials in food packaging due to knowledge gaps, possible interaction with food products and possible health risks that could result from the nano-materials used for food packaging.

The increase in growth and utilisation of nanotechnology signifies wide use of nano-materials especially in the food sector with arrays of potential benefits in the areas of food safety and quality, micronutrients and bioactive ingredients delivery, food processing and in packaging Active studies are being carried out to develop innovative packages such as smart, intelligent and active food packaging to enhance effective and efficient packaging, as well as balanced environmental issues. This review looks at the future of nano-packaged foods vis-à-vis the roles played by stakeholders such as governments, regulatory agencies and manufacturers in looking into consumer health and safety issues related to the application of nano-materials in food packaging.

Nanostructured reactive foils have attracted a great deal of interest recently due to their unique mechanical and thermal properties. Reactive thin foil can be used as a controllable, localized heating source for joining applications, which enable soldering and brazing of materials at room temperature. In this paper, multiphysics-based numerical simulations were performed to simulate reactive thin foils. The conductive heat transfer equation and mass diffusion equations were solved for 1D, 2D, and 3D cases. 1D simulation examined the effect of the chemical reaction rate on the flame speed; 2D simulation gave the detailed temperature and composition distribution in the bi-layers; and 3D simulation demonstrated the localized heating effect of reactive thin foils on a silicon wafer substrate.

The purpose of this paper is study of the type of functional group and its situation on phenyl molecule, in increasing the corrosion protection of modified graphene layers by it. Corrosion protection efficiency of graphene was raised via modifying the surface of graphene-coated carbon steel (CS/G) by using aromatic molecules. Phenyl groups with three different substitutions including COOH, NO₂ and CH₃ grafted to graphene via diazonium salt formation route, by using carboxy phenyl, nitro phenyl and methyl phenyl diazonium salts in ortho, meta and para spatial situations.

Molecular bindings were characterized by using X-ray diffractometer, fourier-transform infrared spectroscopy (FTIR), Raman and scanning electron microscopy (SEM)/ energy dispersive X-ray analysis (EDXA) methods. Anti-corrosion performance of modified CS/G electrodes was evaluated by weight loss and electrochemical techniques, potentiodynamic polarization (Tafel) and electrochemical impedance spectroscopy, in 3.5 per cent NaCl solution.

The obtained results confirmed covalently bonding of phenyl groups to the graphene surface. Also, the observed results showed that substitution spatial situations on phenyl groups can affect charge transfer resistance (R_ct), corrosion potential (E_corr), corrosion current density (j_corr) and the slope of the anodic and cathodic reaction (ß_a,c), demonstrating that the proposed modification method can hinder the corrosion reactions. The proposed modification led to restoring the graphene surface defects and consequently increasing its corrosion protection efficiency.

The obtained results from electrochemical methods proved that protection efficiency was observed in order COOH < NO₂ < CH₃ and MPD in the para spatial situation and showed the maximum protection efficiency of 98.6 per cent in comparison to other substitutions. Finally, the ability of proposed graphene surface modification route was further proofed by using surface methods, i.e. SEM and EDXA, and contact angles measurements.

This study aims to discuss the influences of surface severe plastic deformation (S²PD) on the electrochemical corrosion, pitting corrosion, intergranular corrosion, stress corrosion cracking of aluminum (Al) alloys and attempt to correlate the microstructural/compositional changes with the performances.

This study provides a novel gradient design of structure/composition caused by S²PD for the purpose of enhancing Al alloys’ corrosion resistance.

S²PD has a significant effect on corrosion behavior of Al alloys through tuning the grain size, residual stress, composition, grain boundary phase and second phase particle distribution.

Although Al alloys are known to form a protective Al₂O₃ film, corrosion is a major challenge for the longevity of Al structures across numerous industries, especially for the infrastructures made of high-strength Al alloys. Traditional strategies of improving corrosion resistance of Al alloys heavily relied on alloying and coatings. In this review, gradient design of structure/composition caused by S²PD provides a novel strategy for corrosion protection of Al alloys, especially in the enhancement of localized corrosion resistance.

Shape memory alloys are a fascinating class of materials because they combine both structural and functional properties. These properties strongly depend on temperature. One consequence of this dependency yields the characteristic shape‐memory effect: shape memory alloys can recover processed reference configurations after significant plastic deformations simply upon a change of temperature. For real materials, such processes incorporate characteristic hysteresis. This paper aims at an understanding of these materials from an atomistic point of view.

2D molecular‐dynamics (MD) simulations describing a chain consisting of 32 linked Lennard‐Jones crystals are presented. The crystals consist of nested lattices of two atom species. Distinct lattice structures can be identified, interpreted as austenite and (variants of) martensite. Temperature and/or load‐induced phase transitions between these configurations are observed in MD simulations. Previously, the thermal equation of state of one isolated crystal was investigated and its phase stability was discussed in detail. In the multi‐crystal chain considered in the present paper, individual crystals contribute collectively to the thermo‐mechanical behavior of the assembly.

The paper presents the results of numerical experiments with this polycrystalline chain under strain‐, load‐ and/or temperature‐control. The results show that with the assumption of simple Lennard‐Jones potentials of interaction between atoms in individual crystals and linking these crystals allows to reproduce the features associated with the fascinating behavior of shape memory alloys, including pseudo‐plasticity, pseudo‐elasticity and the shape memory effect.

Owing to the special setup chosen, interfaces are missing between adjacent crystals in the chain assembly. The paper shows that in this situation load‐induced austenite/martensite transitions do not exhibit hysteresis in tension/compression cycles. This observation indirectly supports mesoscopic‐level work in the literature which explicitly introduces interface energy to model such hysteresis.

This report aims to study the influence of applied potentials on the corrosion-wear behavior of 316L stainless steel (SS) in artificial seawater.

In this study, wear-corrosion behavior of 316L SS had been studied under different applied potentials in artificial seawater by using a reformed pin-on-disc test rig. The applied potentials were selected ranging from –1.2 to 0.3 V (vs Ag/AgCl). The friction coefficient, mass loss rate and current density were determined.

It was indicated that mass loss was determined by the combined effect of mechanical wear and chemical corrosion. The wear-corrosion process was synergistic effects dominate while mechanical wear contributed the major material mass loss.

The results helped us to choose the appropriate metals for application under the specified environment.

The main originality of this research is to reveal the corrosion-wear behavior of 316L SS under different potentials, which would help us to understand different states of 316L SS under different corrosion environments.

Different types of wood (ash, oak and beech) have been activated by new activation method. The aim of this work is to study the effect of different types of wood on the physical and chemical properties of Ni/Pd coatings.

The wood was activated by ablation of the Pd target using pulsed laser deposition (PLD) technique. Different diagnostic techniques such as X-ray photoelectron spectroscopy (XPS), attenuated total reflection (ATR) spectroscopy and energy dispersed X-ray spectroscopy (EDS), in parallel with scanning electron microscopy (SEM) were used to achieve this goal.

The XPS technique confirmed that the highest concentration of Pd was found in the Pd/beech sample, which is associated to the texture of the beech wood substrate surface. EDS results confirmed the absence of any contamination related to electroless plating method. It is concluded that the wood morphology and its surface roughness play a conclusive role to obtain different quantity of metal by PLD and electroless plating methods.

Although several works have been performed to study the influence of substrates on the coated metals and away of the traditional methods in activating non-catalytic surface, in this paper, PLD method is used to obtain a good quantity of Pd distributed on the entire surface and inside the porous of the wood. This study could be considered as a step investigation for understanding the role of the wood substrate morphology on the physical and chemical properties of films. To our knowledge, there are no works of combining a coated Ni/Pd by electroless plating and PLD methods on wood.