Nanoemulsions: Preparation, Structure, Functional Properties and their Antimicrobial Effects

Background and Objectives: Recently, due to the interest of healthy lifestyle demand for research on novel methods of increasing the shelf-life of food products without the necessity of using preservatives has extended rapidly in the world. Ability of nanoemulsions to improve global food quality has attracted great attention in food preservation. This is as a result of a number ofattributes peculiar to nanoemulsions such as optical clarity, ease ofpreparation, thermodynamic stability and increased surface area. This review discusses the potential food applications of nanoemulsions as vehicles for the delivery of antimicrobial compounds. Moreover, the preparation, structure, and functional properties of nanoemulsions and their antimicrobial effects on foodborne pathogens and biofilms will be reviewed in detail. Antimicrobial nanoemulsions are formulated from the antimicrobial compounds that are approved by the Food and Drug Administration (FDA) for use in foods.Results and Conclusion: The antimicrobial activity of nanoemulsions is nonspecific, unlike that of antibiotics, thus they have a broad-spectrum of antimicrobial activity against bacteria (e.g., Escherichia coli, Salmonella, and Staphylococcus aureus), enveloped viruses (e.g., HIV, and herpes simplex), fungi (e.g., Candida, Dermatophytes), and spores (e.g., anthrax) at concentrations that are nontoxic in animals (while limiting the capacity for the generation of resistance) and kill pathogens by interacting with their membranes. This physical kill-on-contact mechanism significantly reduces the possibility of the emergence of resistant strains. In general, more research is needed to improve the application processes of antimicrobial nanoemulsion, especially sensory aspects, to be appropriate for each product.Conflict of interests: The authors declare no conflict of interest

A review and comparison on some rubber elasticity models

This study reviews several classical continuum mechanics models for incompressible and isotropic materials based onstrain energy potential and then compares ability of neo-Hookean, Yeoh, Mooney-Rivlin and Ogden models in predicting uniaxialdeformation states based on experimental data from dumb-bell test specimen under uniaxial loading

Characterization of shot peened 2024-T351 aluminum alloy

Specimens of 2024-T351 aluminium alloy under different three shot peening intensities were studied. The modifications of the surface layers of the shot peened specimens were investigated through microhardness, surface microstructure and residual stress relaxation after the first and second load cycles under two cyclic loads. No significant changes in microstructure after the three shot peeing intensities were observed with respect to untreated specimens. Rapid residual stress relaxation was observed in specimens after the first cycle. Relaxation of residual stresses occurred within first loading cycles were increased with increasing loading stress amplitude and due to quasi-static relaxation effects

Prediction of residual stress relaxation of shot peened 2024-T351 aluminum alloy: part 1

It is important to account for residual stress relaxation phenomenon in the design of the component. Specimens of 2024-T351 aluminium alloy were used in this study. The specimens were shot peened under three different shot peening intensities. Cyclic tests for two load magnitudes were performed for 1, 2, 10, 1000 and 10000 cycles. Residual stresses, microhardness and the cold work percentage were measured at initial state and after each loading cycle for the three shot peening intensities and for the two loads. The study revealed that most of the drop in the residual stress, microhardness and cold work happened in the first cycle are dependent on the applied load

Auto generation of the center of gravity of tubular structures during crush deformation

Displacement of the center of gravity (COG) of tubular structures with various polygonal cross-sections is numerically investigated under an axial crush using the program code of ANSYS/LS-DYNA. A subroutine is developed using this code to calculate the COG of the deformed shape, during and after the crush. The effect of wall thickness on displacement of the COG is also investigated. Displacement of the COG decreases as the number of edges increases; it is a reasonable symmetric-deformed shape for the number of edges beyond eight. An even number of edges leads to a more symmetric displacement of the COG. The effect of the number of polygonal edges on symmetric deformation of the COG becomes more prominent as the initial wall thickness decreases. The higher number of edges stabilizes the deformed shape and the value of the mass moment of inertia of the deformed shape about the y axis (Iyy). The value of the mass moment of inertia about the x-z axes (Ixz) in comparison with I yy can be neglected in the case of dealing with an axial crush along the y direction

Evidence of relationships between teaches’ leadership style practices for learning and student academic press/emphasis

The purpose of the study was to investigate the relationship between teachers’ leadership styles practices for learning with students’ academic press/emphasis (AP/AE) at selected secondary schools in Kuala Lumpur. The study employed a quantitative research design to address the research problems and two research hypotheses. A total of 328 students from three selected secondary schools in Kuala Lumpur was randomly selected to complete the survey questionnaires of the study. The data were statistically analysed using confirmatory factor analysis and structural equation modelling. The results showed that the English subject teachers at the selected national secondary schools exhibited clearly the two leadership styles practices (COE and COA) as it supported the hypotheses that the two predictors were adequate to explain students’ AP/AE, particularly COA which was the most influential predictor. This study therefore adds a new dimension to the body of knowledge that will help researchers’ efforts to understand the relationship between English subject teachers’ leadership styles practices and students’ AP/AE. As this study takes place in the Malaysian context, it definitely contributes to the enriching of the indigenous body of knowledge. The implication would be in terms of the teacher training and enhancement of teacher professional development programmes. Keywords: teachers’ leadership styles; academic press; English; quantitativ

Modelling of residual stress relaxation : a review

Compressive residual stress, induced by mechanical surface treatment, may relax during component operation life, due to thermal or mechanical mechanism. Fatigue life prediction for the components which have residual stress will be misled and inaccurately predicted the phenomenon of residual stress relaxation is not considered. Despite putting an effort on incorporating the residual stress relaxation, the issues remain concerned with the technical challenge of measuring and quantifying the magnitude of residual stress relaxation as well as redistribution during the loading cycling itself. In this paper, the residual stress relaxation and its models were reviewed and discussed to picture the best knowledge related to this topic, i.e. whether relaxation is a cause or an effect

Residual stress relaxation and surface hardness of a 2024-t351 aluminium alloy

For design it is generally important to consider the residual stress relaxation. In the study for this contribution, 2024 T351 Aluminium alloy specimens were shot peened at three different shot peening intensities, followed by fatigue tests for two loads. Fatigue tests were divided into two stages. The residual stresses and micro-hardness were measured at initial and after each cyclic load for the three shot peening intensities and the two aforementioned sets of loads. The results showed that the residual stresses and micro-hardness of the specimens were decreased. Moreover, the relaxation depended on the fatigue load amplitude. Residual stress relaxation reached 54% of the initial residual stress while the micro-hardness relaxation reached 39% of the initial micro-hardness. Most of the residual stress relaxation occurred during the first cycle. The relaxation of the initial residual stress is severe when there is low shot peening intensity and high applied load, and the reduction of the micro-hardness is depending on the residual stress relaxation

Analysis of the learning object-oriented programming factors

Students often feel overwhelmed by object-oriented programming courses. They find it difficult and complex to learn, requiring a high cognitive load to use the concepts in coding. These issues lead to demotivation in learning programming. This research aims to identify and verify factors that contribute to learning object-oriented programming from two perspectives: interviews and surveys. A literature review was conducted to identify these factors, followed by interviews with five experts who have been teaching object-oriented programming for over ten years to confirm them. Based on the interview results, a questionnaire was developed and administered to 31 bachelor students and 19 lecturers with master’s or doctorate degrees in computer science. The responses indicated that the identified factors were acceptable, with scores ranging from 3.74 to 4.65. The outcomes of this study are a set of factors that should be considered in a programming environment to improve the teaching and learning of object-oriented programming and make it more accessible and engaging for students

Modelling of residual stress relaxation: a review

Compressive residual stress, induced by mechanical surface treatment, may relax during component operation life, due to thermal or mechanical mechanism. Fatigue life prediction for the components which have residual stress will be misled and inaccurately predicted the phenomenon of residual stress relaxation is not considered. Despite putting an effort on incorporating the residual stress relaxation, the issues remain concerned with the technical challenge of measuring and quantifying the magnitude of residual stress relaxation as well as redistribution during the loading cycling itself. In this paper, the residual stress relaxation and its models were reviewed and discussed to picture the best knowledge related to this topic, i.e. whether relaxation is a cause or an effect