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1 – 10 of over 4000
Article
Publication date: 12 December 2019

Jasmeet Kour, Sukhcharn Singh and Dharmesh C. Saxena

The purpose of this paper is to investigate the effect of residence time distribution in extruders along with the incorporation of nutraceuticals on the final quality of the…

Abstract

Purpose

The purpose of this paper is to investigate the effect of residence time distribution in extruders along with the incorporation of nutraceuticals on the final quality of the products with respect to several pivotal responses.

Design/methodology/approach

Corn–rice flour blend fortified with isolated nutraceutical concentrates at two (low and high) levels was extruded at barrel temperature (110°C), screw speed (260 rpm) and feed moisture (17 percent). Extrudates were collected at an interval of 24 s followed by analysis for radial expansion (RE), bulk density (BD), water absorption index (WAI), sensory score (SS), textural hardness, colorimetric values (L*, a* and b*) and color difference (E).

Findings

The entire data were fitted to zero- and first-order kinetic models. There was a gradual decrease in RE, SS and L* value, whereas an increase in BD, textural hardness and a* value of extrudates fortified with the three nutraceutical concentrates was observed with the successive time interval of 24 s along with a more pronounced effect on color difference (E) observed during the last stages of extrusion time. The zero-order kinetic model was well fitted for BD and a* value, whereas the first-order kinetic model showed better results for RE, WAI, SS, textural hardness, L* value, a* value and b* value of fortified extrudates.

Originality/value

Nutraceuticals like β-glucans, lignans and γ oryzanol exhibit numerous health-beneficial effects. This study analyzes the kinetics of changes in various responses of extrudates fortified with these nutraceutical concentrates during extrusion.

Details

British Food Journal, vol. 122 no. 2
Type: Research Article
ISSN: 0007-070X

Keywords

Article
Publication date: 23 August 2011

Yaser Jafarian, Mohammad H. Baziar, Mohammad Rezania and Akbar A. Javadi

In this paper, the peak kinetic energy density (KED) of soil particles during earthquake excitation is used as an intensity measure for the evaluation of liquefaction potential…

Abstract

Purpose

In this paper, the peak kinetic energy density (KED) of soil particles during earthquake excitation is used as an intensity measure for the evaluation of liquefaction potential under field conditions. The paper seeks to discuss this measure.

Design/methodology/approach

Using centrifuge tests data, it is shown that seismic pore water pressure buildup is proportional to cumulative KED at a particular soil depth. Linear relationships are found between cumulative kinetic energy and corresponding cumulative strain energy. To consider the effect of soil amplification, several equivalent linear ground response analyses are performed and the results are used to derive an equation for depth reduction factor of peak kinetic energy density. Two separate databases of liquefaction case histories are used in order to validate the proposed model. The performance of the proposed model is compared with a number of commonly used shear stress‐based liquefaction assessment methods. Finally, the logistic regression method is employed to obtain probabilistic boundary curves based on the present model. Parametric study of the proposed probabilistic model is carried out to verify its agreement with the previous methods.

Findings

It has been shown that the kinetic energy model works satisfactorily in classifying liquefied and non‐liquefied cases compared with the existing recommendations of shear stress‐based criterion. The results of the probabilistic kinetic energy model are in good agreement with those of previous studies and show a reasonable trend with respect to the variations of fines content and effective overburden pressure. The proposed model can be as used an alternative approach for assessment of liquefaction potential.

Originality/value

These findings make a sound basis for the development of a kinetic energy‐based method for assessment of liquefaction potential.

Details

Engineering Computations, vol. 28 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 14 June 2022

Qi Xiao

The paper aims to build a finite element simulation model for pilling of polyester hairiness on the fabric to study the effects of hairiness performance on pilling and reveal…

Abstract

Purpose

The paper aims to build a finite element simulation model for pilling of polyester hairiness on the fabric to study the effects of hairiness performance on pilling and reveal pilling mechanisms.

Design/methodology/approach

The finite element simulation model of pilling of polyester hairiness was established by ABAQUS. Polyester hairiness was treated as elastic thin rod, which was divided by two-node linear three-dimensional truss element. The effects of hairiness elastic modulus, hairiness friction coefficient and hairiness diameter on frictional dissipation energy, strain energy and kinetic energy produced by pilling have been studied. The analysis solution values were compared with the finite element simulation results, which was used to verify finite element simulation.

Findings

The paper provides new insights about how to reveal pilling mechanisms of polyester hairiness with different performance. Comparing finite element simulation results with analysis solutions shows that the fitness is greater than 0.96, which verifies finite element simulation. Larger hairiness elastic modulus gives rise to higher friction dissipation energy and strain energy of hairiness but lower kinetic energy. Increasing friction coefficient enhances friction dissipation and strain energy of hairiness. However, kinetic energy decreases with the increase of friction coefficient. Hairiness diameter also has an important effect on hairiness entanglement and pilling. Increasing hairiness diameter can decrease friction dissipation energy but enhance strain energy and kinetic energy.

Research limitations/implications

Finite element simulation was verified by analysis solutions. The solutions include friction dissipation energy, strain energy and kinetic energy, which cannot measured b experiment. Therefore, researchers are encouraged to simulate pilling to obtain pilling grades, which be compared with experiment results.

Originality/value

Pilling of polyester hairiness was simulated by ABAQUS. This method makes pilling process visualization, and pilling mechanisms was revealed from non-linear dynamics.

Details

International Journal of Clothing Science and Technology, vol. 34 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 6 February 2018

Li Wang and Qingpu Zhang

Internet-based intangible network good (IING) has revolutionized multiple industries in recent years. This paper aims to reveal the laws of consumer’s decision-making on IING from…

Abstract

Purpose

Internet-based intangible network good (IING) has revolutionized multiple industries in recent years. This paper aims to reveal the laws of consumer’s decision-making on IING from a perspective of kinetic energy and potential energy.

Design/methodology/approach

In this paper, 4 aspects and 17 factors influencing IING adoption were generalized. Based on the theory of social physics, an agent-based simulation model, introducing physical energy theory to depict consumer’s decision-making, was built. An agent’s kinetic energy reflects the agent’s perceived effect of mass media on the agent’s decision-making on IING adoption. An agent’s potential energy reflects the agent’s perceived effect of social interactions on the agent’s decision-making on the adoption of IING. An agent’s final energy is the sum of the kinetic energy and potential energy, which reflects the agent’s final decision.

Findings

Some factors mainly influence the diffusion velocity, while other factors have a dramatic impact on both diffusion velocity and diffusion scale. The agent’s personality can make a difference at the early and middle stages of IING adoption, but a faint impact at the later stage because of the effects of network externalities and word of mouth. There is a critical value of the number of initial adopters which can dramatically speed up IING adoption.

Practical implications

This study provides new insights for firms on the effects of factors influencing consumers’ decision-making on IING adoption.

Originality/value

This paper defines a new kind of innovation, IING, and generalizes IING’s special characteristics. As a new application of social physics, the physical energy theory has been creatively introduced to depict consumer’s decision-making on IING adoption. A kinetic and potential energy model of IING adoption has been built. Based on simulation experiments, new insights of IING adoption have been gained.

Article
Publication date: 1 June 1994

B. H. V. Topping and A. I. Khan

This paper describes a parallel algorithm for the dynamic relaxation(DR) method. The basic theory of the dynamic relaxation is brieflyreviewed to prepare the reader for the…

Abstract

This paper describes a parallel algorithm for the dynamic relaxation (DR) method. The basic theory of the dynamic relaxation is briefly reviewed to prepare the reader for the parallel implementation of the algorithm. Some fundamental parallel processing schemes have been explored for the implementation of the algorithm. Geometric Parallelism was found suitable for the DR method when using transputer‐based systems. The evolution of the parallel algorithm is given by identifying the steps which may be executed in parallel. The structure of the parallel code is discussed and then described algorithmically. Two geometrically non‐linear parallel finite element analyses have been performed using different mesh densities. The number of processors was varied to investigate algorithm efficiency and speed ups. Using the results obtained it is shown that the computational efficiency increases when the computational load per processor is increased.

Details

Engineering Computations, vol. 11 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 February 2006

C.M. Winkler and Sarma L. Rani

To evaluate the performance of different subgrid kinetic energy models across a range of Reynolds numbers while keeping the grid constant.

Abstract

Purpose

To evaluate the performance of different subgrid kinetic energy models across a range of Reynolds numbers while keeping the grid constant.

Design/methodology/approach

A dynamic subgrid kinetic energy model, a static coefficient kinetic energy model, and a “no‐model” method are compared with direct numerical simulation (DNS) data at two friction Reynolds numbers of 180 and 590 for turbulent channel flow.

Findings

Results indicate that, at lower Reynolds numbers, the dynamic model more closely matches DNS data. As the amount of energy in the unresolved scales increases, the performance of both kinetic energy models is seen to decrease.

Originality/value

This paper provides guidance to engineers who routinely use a single grid to study a wide range of flow conditions (i.e. Reynolds numbers), and what level of accuracy can be expected by using kinetic energy models for large eddy simulations.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 16 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 1 April 1994

Ming‐C. Cheng and Ying Wen

Accuracy of hydrodynamic transport equations using the energy‐dependent relaxation times has been studied for electron transport in Si 〈100〉. The concept of the hydro‐kinetic

Abstract

Accuracy of hydrodynamic transport equations using the energy‐dependent relaxation times has been studied for electron transport in Si 〈100〉. The concept of the hydro‐kinetic transport model is used to describe non‐equilibrium electron transport phenomena and to examine the validity for the assumption of energy‐dependent relaxation times. It has been shown that under the influence of a drastic increase in field the relaxation times might also strongly depend on the average velocity near the peak of strong velocity overshoot. In addition, the velocity dependence is found to be more pronounced at lower temperatures in Si 〈100〉.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 4
Type: Research Article
ISSN: 0332-1649

Article
Publication date: 1 January 1984

M. Geradin and N. Kill

A 3‐dimensional formalism adapted to critical speed and stability analysis of rotating machinery is presented. Gyroscopic effects are properly taken into account in the expression…

Abstract

A 3‐dimensional formalism adapted to critical speed and stability analysis of rotating machinery is presented. Gyroscopic effects are properly taken into account in the expression of the kinetic energy through a proper kinematic description which takes account of the local changes of angular velocity induced by the deformation. Two approaches are suggested according to the respective stiffness and geometric properties of the rotating and fixed parts: the rotating frame approach and the inertial frame approach. In both cases, an axisymmetric finite element modelling of the rotor is proposed which takes into account the 3‐dimensional nature of the system while keeping the number of degrees of freedom to a reasonable level. In order to perform the stability analysis, a preliminary reduction of the system is achieved using the component mode method. Critical speeds are calculated next either by the classical sweeping procedure or by a direct method when the restrictive conditions of its applicability are met. The concepts proposed are then applied to an example in order to demonstrate their adequacy.

Details

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

Article
Publication date: 4 May 2020

Felipe Pathe Duarte

This paper aims to understand whether Portugal, being a relatively peripheral country – in political, economic and military terms – of Southwest Europe, was recently a target of…

Abstract

Purpose

This paper aims to understand whether Portugal, being a relatively peripheral country – in political, economic and military terms – of Southwest Europe, was recently a target of hybrid threats. The prevalence of a specific type of threat was found. Thus, this paper analyses the non-kinetic hybrid threats in Portugal, in a temporary hiatus of two years (2017-2018).

Design/methodology/approach

This study has two parts: a conceptual analysis of hybrid threats created by us and, based on the typology previously presented, an analysis of the hybrid threats in Portugal between 2017 and 2018. The first part relied on source analysis, as the result of a desk review methodology, supported by monographs, declassified official documents and reports. The second part is also the result of source analysis, but more extensive. In addition to the desk review methodology, the study included semi-structured interviews with different stakeholders from the Portuguese security and armed forces, who asked not to be quoted. Media content analysis was also carried out – for trends and fact-check – mostly for the events related to the “narratives led operations” (for propaganda, misinformation, counter-information and strategic leaks).

Findings

To date, Portugal – compared with other European states – has not been a significant target for hybrid threats. It is diluted in the Portuguese geopolitical dimension. Nevertheless, not escaping what is happening in Europe, it has also been the target of non-kinetic hybrid threats, especially in cyberspace. In the field of so-called “narrative-driven operations”, there have been some occurrences – whether related to fake news, far-right movements or strategic leaks. In addition, cyberattacks from foreign groups for information and data gathering have increased in recent years, making governmental and private critical infrastructures more vulnerable.

Research limitations/implications

One of the characteristics of hybrid threats is their difficult identification. Therefore, information is scarce, which has complicated the research, leading us to assume, in many cases, speculation about the threat. It should also be taken into account that, in the case of cyberspace, until 2018, 90% of the occurrences were not reported, and the study has dealt with only official numbers.

Originality/value

It is not a policy paper. Although it neither points out national vulnerabilities to this type of threat nor makes procedural recommendations or considerations, it is fundamental in identifying the peculiarity of hybrid threats in a democratic state.

Details

Transforming Government: People, Process and Policy, vol. 14 no. 3
Type: Research Article
ISSN: 1750-6166

Keywords

Article
Publication date: 5 February 2018

Nathan Grange, Pietro Tadini, Khaled Chetehouna, Nicolas Gascoin, Guillaume Bouchez, Samuel Senave and Isabelle Reynaud

The purpose of this paper is to evaluate the fire resistance of an innovative carbon-reinforced PEKK composite for aeronautical applications. To this end, thermal degradation…

Abstract

Purpose

The purpose of this paper is to evaluate the fire resistance of an innovative carbon-reinforced PEKK composite for aeronautical applications. To this end, thermal degradation analysis under inert and oxidative atmosphere is carried out. Moreover, a linear model fitting approach is compared to a generally used isoconversional method to validate its reliability for kinetic triplet estimation.

Design/methodology/approach

Thermogravimetric analysis carried out under inert and oxidative atmospheres, between 25 and 1000°C for three different heating rates (5, 15, 25°C/min), followed by a qualitative SEM observation of the samples before and after thermal treatment. After the reaction identification by TG/DTG curves, an isoconversional analysis is carried out to estimate the activation energy as a function of the reaction conversion rate. For the identified reactions, the kinetic triplet is estimated by different methods and the results are compared to evaluate their reliability.

Findings

In inert case, one global reaction, observed between 500-700°C, seems able to describe the degradation of carbon-PEKK resin. Under oxidative atmosphere, three main reactions are identified, besides the resin degradation, the other two are attributed to char and fiber oxidation. Good agreement achieved between isoconversional and linear model fitting methods in activation energy calculation. The achieved results demonstrate the high thermal resistance of PEKK associated with the ether and ketone bonds between the three aromatic groups of its monomer.

Originality/value

This paper provides a possible degradation model useful for numerical implementation in CFD calculations for aircraft components design, when exposed to high temperatures and fire conditions.

Details

International Journal of Structural Integrity, vol. 9 no. 1
Type: Research Article
ISSN: 1757-9864

Keywords

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