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11 – 20 of over 2000
Article
Publication date: 3 July 2017

Zaher Rahimi, Wojciech Sumelka and Xiao-Jun Yang

Recently, a new formulation has been introduced for non-local mechanics in terms of fractional calculus. Fractional calculus is a branch of mathematical analysis that studies the…

Abstract

Purpose

Recently, a new formulation has been introduced for non-local mechanics in terms of fractional calculus. Fractional calculus is a branch of mathematical analysis that studies the differential operators of an arbitrary (real or complex) order and is used successfully in various fields such as mathematics, science and engineering. The purpose of this paper is to introduce a new fractional non-local theory which may be applicable in various simple or complex mechanical problems.

Design/methodology/approach

In this paper (by using fractional calculus), a fractional non-local theory based on the conformable fractional derivative (CFD) definition is presented, which is a generalized form of the Eringen non-local theory (ENT). The theory contains two free parameters: the fractional parameter which controls the stress gradient order in the constitutive relation and could be an integer and a non-integer and the non-local parameter to consider the small-scale effect in the micron and the sub-micron scales. The non-linear governing equation is solved by the Galerkin and the parameter expansion methods. The non-linearity of the governing equation is due to the presence of von-Kármán non-linearity and CFD definition.

Findings

The theory has been used to study linear and non-linear free vibration of the simply-supported (S-S) and the clamped-free (C-F) nano beams and then the influence of the fractional and the non-local parameters has been shown on the linear and non-linear frequency ratio.

Originality/value

A new parameter of the theory (the fractional parameter) makes the modeling more fixable – this model can conclude all of integer and non-integer operators and is not limited to special operators such as ENT. In other words, it allows us to use more sophisticated mathematics to model physical phenomena. On the other hand, in the comparison of classic fractional non-local theory, the theory applicable in various simple or complex mechanical problems may be used because of simpler forms of the governing equation owing to the use of CFD definition.

Details

Engineering Computations, vol. 34 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 29 May 2020

Shilpi Birla, Sudip Mahanti and Neha Singh

The purpose of this paper is to propose a leakage reduction technique which will works for complementary metal oxide semiconductor (CMOS) and fin field effect transistor (FinFET)…

Abstract

Purpose

The purpose of this paper is to propose a leakage reduction technique which will works for complementary metal oxide semiconductor (CMOS) and fin field effect transistor (FinFET). Power consumption will always remain one of the major concerns for the integrated circuit (IC) designers. Presently, leakage power dominates the total power consumption, which is a severe issue. It is undoubtedly clear that the scaling of CMOS revolutionizes the IC industry. Still, on the contrary, scaling of the size of the transistor has raised leakage power as one of the significant threats to the IC industry. Scaling of the devices leads to the scaling of other device parameters, which includes threshold voltage also. The scaling of threshold voltage leads to an exponential increase in the sub-threshold current. So, many leakage reduction techniques have been proposed by researchers for CMOS from time to time. Even the other nano-scaled devices such as FinFET, carbon nanotube field effect transistor and tunneling field effect transistor, have been introduced, and FinFET is the one which has evolved as the most favorable candidate for replacing CMOS technology.

Design/methodology/approach

Because of its minimum leakage and without having limitation of the short channel effects, it gradually started replacing the CMOS. In this paper, the authors have proposed a technique for leakage reduction for circuits using nano-scaled devices such as CMOS and FinFET. They have compared the proposed PMOS FOOTER SLEEP with the existing leakage reduction techniques such as LECTOR technique, LECTOR FOOTER SLEEP technique. The proposed technique has been implemented using CMOS and FinFET devices. This study found that the proposed method reduces the average power, as well as leakage power reduction, for both CMOS and FinFET devices.

Findings

This study found that the proposed method reduces the average power as well as leakage power reduction for both CMOS and FinFET devices. The delay has been calculated for the proposed technique and the existing techniques, which verifies that the proposed technique is suitable for high-speed circuit applications. The authors have implemented higher order gates to verify the performance of the proposed circuit. The proposed method is suitable for deep-submicron CMOS technology and FinFET technology.

Originality/value

All the existing techniques were proposed for either CMOS device or FinFET device, but the authors have implemented all the techniques with both the devices and verified with the proposed technique for CMOS as well as FinFET devices.

Article
Publication date: 14 November 2008

George K. Stylios

Examines the fourteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…

1248

Abstract

Examines the fourteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

Details

International Journal of Clothing Science and Technology, vol. 20 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 20 November 2020

Rajendran Selvamani, M. Mahaveer Sree Jayan and Farzad Ebrahimi

The purpose of this paper is concerned with the study of nonlinear ultrasonic waves in a magneto-flexo-thermo (MFT) elastic armchair single-walled carbon nanotube (ASWCNT) resting…

Abstract

Purpose

The purpose of this paper is concerned with the study of nonlinear ultrasonic waves in a magneto-flexo-thermo (MFT) elastic armchair single-walled carbon nanotube (ASWCNT) resting on polymer matrix.

Design/methodology/approach

A mathematical model is developed for the analytical study of nonlinear ultrasonic waves in a MFT elastic armchair single walled carbon nanotube rested on polymer matrix using Euler beam theory. The analytical formulation is developed based on Eringen’s nonlocal elasticity theory to account small scale effect. After developing the formal solution of the mathematical model consisting of partial differential equations, the frequency equations have been analysed numerically by using the nonlinear foundations supported by Winkler-Pasternak model. The solution is obtained by ultrasonic wave dispersion relations.

Findings

From the literature survey, it is evident that the analytical formulation of nonlinear ultrasonic waves in an MFT elastic ASWCNT embedded on polymer matrix is not discussed by any researchers. So, in this paper the analytical solutions of nonlinear ultrasonic waves in an MFT elastic ASWCNT embedded on polymer matrix are studied. Parametric studies is carried out to scrutinize the influence of the nonlocal scaling, magneto-electro-mechanical loadings, foundation parameters, various boundary condition and length on the dimensionless frequency of nanotube. It is noticed that the boundary conditions, nonlocal parameter and tube geometrical parameters have significant effects on dimensionless frequency of nanotubes.

Originality/value

This paper contributes the analytical model to find the solution of nonlinear ultrasonic waves in an MFT elastic ASWCNT embedded on polymer matrix. It is observed that the increase in the foundation constants raises the stiffness of the medium and the structure is able to attain higher frequency once the edge condition is C-C followed by S-S. Further, it is noticed that the natural frequency is arrived below 1% in both local and nonlocal boundary conditions in the presence of temperature coefficients. Also, it is found that the density and Poisson ratio variation affects the natural frequency with below 2%. The results presented in this study can provide mechanism for the study and design of the nano devices such as component of nano oscillators, micro wave absorbing, nano-electron technology and nano-electro--magneto-mechanical systems that make use of the wave propagation properties of ASWCNTs embedded on polymer matrix.

Details

World Journal of Engineering, vol. 18 no. 1
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 13 November 2009

George K. Stylios

Examines the fifthteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects…

1098

Abstract

Examines the fifthteenth published year of the ITCRR. Runs the whole gamut of textile innovation, research and testing, some of which investigates hitherto untouched aspects. Subjects discussed include cotton fabric processing, asbestos substitutes, textile adjuncts to cardiovascular surgery, wet textile processes, hand evaluation, nanotechnology, thermoplastic composites, robotic ironing, protective clothing (agricultural and industrial), ecological aspects of fibre properties – to name but a few! There would appear to be no limit to the future potential for textile applications.

Details

International Journal of Clothing Science and Technology, vol. 21 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 1 December 2005

Per Dannemand Andersen, Birgitte Rasmussen, Marianne Strange and Jens Haisler

The purpose is to report on a Danish nano‐science and nano‐technology foresight project carried out in 2004.

1441

Abstract

Purpose

The purpose is to report on a Danish nano‐science and nano‐technology foresight project carried out in 2004.

Design/methodology/approach

The foresight process had the following key elements: review of international technology foresight projects on nano‐technology; mapping of Danish nano‐science and nano‐technology; broad internet survey among interested parties; expert reports; workshops related to the expert reports; analysis of the dynamics of innovation within nano‐technology; survey on hazards and environmental and ethical aspects; group interviews with members of the public.

Findings

The article reflects on the following methodological issues: domain classification and its influence on conclusions; the use of statements or hypotheses; trustworthiness of the foresight process and its recommendations.

Practical implications

Recommendations from the project have already been used in decision‐making on R&D funding and in strategic deliberation in publicly funded institutions conducting R&D. Others are expected to be used for decision‐making, and some are being discussed in research councils and ministries or are being investigated and developed further. Moreover, the foresight process has created broader awareness of, and debate especially about, the hazardous aspects of nano‐technology among researchers and decision makers.

Originality/value

The article contribute the to the European experiences with national level foresight exercises. The case and the findings are of value for science and innovation policy makers, foresight practitioners and scolars within the field.

Details

Foresight, vol. 7 no. 6
Type: Research Article
ISSN: 1463-6689

Keywords

Article
Publication date: 12 March 2018

Yuan Wang

The main purpose of this study is to enhance bio-tribological properties of Ti6Al4V and the surface-modified layers of Ni+/N+-implanted Ti6Al4V alloy, bionic texturing was done on…

Abstract

Purpose

The main purpose of this study is to enhance bio-tribological properties of Ti6Al4V and the surface-modified layers of Ni+/N+-implanted Ti6Al4V alloy, bionic texturing was done on Ti6Al4V surface.

Design/methodology/approach

The phase compositions and nano-hardness of the surface-modified layers of the samples have been analyzed by X-ray diffractometer and Nano Indenter, respectively. This paper has conducted bio-tribological tests under artificial saliva, sodium hyalurate and sodium hyalurate +γ-globulin by micro tribology multifunction tribometer, with ZrO2 ball/modified layer as the friction pair. S-3000N scanning electron microscope has been used to analyze the morphology of the surface-modified layers and scratches of the ones after the bio-tribological tests.

Findings

The results show that the surface-modified layers were mainly composed of Ti2Ni and Ti2N. Moreover, bionic texturing can obviously increase the contents of Ti2Ni and Ti2N that were formed on the surface of Ni+/N+-implanted Ti6Al4V alloy, and enhance the nano-hardness of the surface-modified layers. It could also reduce the friction coefficients of the surface-modified layers, and render the modified layers more wear-resistant.

Originality/value

The surface bio-tribological properties of Ti6Al4V have been enhanced by ion implantation technique and bionic texturing in this paper; this provided a new method for the research of related fields.

Details

Industrial Lubrication and Tribology, vol. 70 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 4 January 2011

Stoyan Stoyanov, Tim Tilford, Farid Amalou, Scott Cargill, Chris Bailey and Marc Desmulliez

Nano‐imprint forming (NIF) is a manufacturing technology capable of achieving high resolution, low‐cost and high‐throughput fabrication of fine nanoscale structures and patterns…

Abstract

Purpose

Nano‐imprint forming (NIF) is a manufacturing technology capable of achieving high resolution, low‐cost and high‐throughput fabrication of fine nanoscale structures and patterns. The purpose of this paper is to use modelling technologies to simulate key process steps associated with the formation of patterns with sub‐micrometer dimensions and use the results to define design rules for optimal imprint forming process.

Design/methodology/approach

The effect of a number of process and pattern‐related parameters on the quality of the fabricated nano‐structures is studied using non‐linear finite element analysis. The deformation process of the formable material during the mould pressing step is modelled using contact analysis with large deformations and temperature dependent hyperelastic material behaviour. Finite element analysis with contact interfaces between the mould and the formable material is utilised to study the formation of mechanical, thermal and friction stresses in the pattern.

Findings

The imprint pressure, temperature and the aspect ratio of grooves which define the pattern have significant effect on the quality of the formed structures. The optimal imprint pressure for the studied PMMA is identified. It is found that the degree of the mould pattern fulfilment as function of the imprint pressure is non‐linear. Critical values for thermal mismatch difference in the CTE between the mould and the substrate causing thermally induced stresses during cooling stage are evaluated. Regions of high stresses in the pattern are also identified.

Originality/value

Design rules for minimising the risk of defects such as cracks and shape imperfections commonly observed in NIF‐fabricated nano‐structures are presented. The modelling approach can be used to provide insights into the optimal imprint process control. This can help to establish further the technology as a viable route for fabrication of nanoscale structures and patterns.

Details

Engineering Computations, vol. 28 no. 1
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 8 June 2015

Mica Grujicic, Ramin Yavari, Jennifer Snipes and S Ramaswami

In the present work, a new blast-/ballistic-impact mitigation concept is introduced and its efficacy analyzed using advanced computational methods and tools. The concept involves…

Abstract

Purpose

In the present work, a new blast-/ballistic-impact mitigation concept is introduced and its efficacy analyzed using advanced computational methods and tools. The concept involves the use of a zeolite protective layer separated by air from the structure being protected and in contact with a water layer in front. The paper aims to discuss these issues.

Design/methodology/approach

To properly capture the attendant nano-fluidics phenomena, all the calculations carried out in the present work involved the use of all-atom molecular-level equilibrium and non-equilibrium molecular-dynamics simulations.

Findings

Under high-rate loading, water molecules (treated as a nano-fluidic material) are forced to infiltrate zeolite nanopores wherein, due to complex interactions between the hydrophobic nanopore walls and the hydrogen bonds of the water molecules, water undergoes an ordering-type phase transition and acquires high density, while a significant portion of the kinetic energy of the water molecules is converted to potential energy. Concomitantly, a considerable portion of this kinetic energy is dissipated in the form of heat. As a result of these energy conversion/dissipation processes, the (conserved) linear momentum is transferred to the target structure over a longer time period, while the peak loading experienced by the structure is substantially reduced.

Originality/value

To the authors’ knowledge, the present work constitutes the first reported attempt to utilize pure SiO2 hydrophobic zeolites in blast-/ballistic-impact protection applications.

Details

International Journal of Structural Integrity, vol. 6 no. 3
Type: Research Article
ISSN: 1757-9864

Keywords

Article
Publication date: 11 November 2019

Samuel Ayofemi Olalekan Adeyeye

Nanotechnology as an emerging area if adequately harnessed could revolutionise food packaging and food processing industry worldwide. Although several benefits of nano-materials…

1547

Abstract

Purpose

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.

Design/methodology/approach

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

Findings

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.

Originality/value

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.

Details

Nutrition & Food Science , vol. 49 no. 6
Type: Research Article
ISSN: 0034-6659

Keywords

11 – 20 of over 2000