The purpose of this paper is to investigate squeezing and rotating motions between two rough parallel circular discs lubricated by piezo – viscous couple stress lubricant with…
Abstract
Purpose
The purpose of this paper is to investigate squeezing and rotating motions between two rough parallel circular discs lubricated by piezo – viscous couple stress lubricant with pressure-dependent viscosity variation.
Design/methodology/approach
Based upon the Stokes couple stress theory, Barus viscosity-pressure dependency relation and Christensen rough surfaces model, squeeze film characteristics between two rough parallel circular discs are obtained.
Findings
According to the results, it is found that, the combined effects of couple stresses and viscosity-pressure dependency increases squeeze film performance with respect to the classical Newtonian iso-viscous (constant viscosity) lubricant. However, increasing the rotational inertia parameter reduces squeeze film characteristics. On the other hand, depending on the structure of surface roughness, the squeeze film characteristics can be increased or decreased. Furthermore, results show that the surface roughness with circular pattern increases squeeze film characteristics, while the surface roughness with radial pattern will decrease it.
Originality/value
This paper is relatively original and describes the squeeze film characteristics between two parallel circular discs with viscosity-pressure dependency, rotational inertia, couple stresses and surface roughness effects.
Details
Keywords
The purpose of this paper is to investigate squeezing and rotating motions between two rough parallel circular discs lubricated by ferro-fluid couple stress lubricant.
Abstract
Purpose
The purpose of this paper is to investigate squeezing and rotating motions between two rough parallel circular discs lubricated by ferro-fluid couple stress lubricant.
Design/methodology/approach
Based upon the Stokes couple stress theory, ferro-hydrodynamic model of Shliomis and Christensen rough surfaces model, squeeze-film characteristics between two rough parallel circular discs considering rotational inertia effects are obtained.
Findings
According to the results, it is found that the combined effects of couple stresses and ferro-fluid lubricants increases squeeze film performance with respect to the classical Newtonian lubricant. However, increasing the rotational inertia parameter reduces squeeze film characteristics. On the other hand, depending on the structure of surface roughness, the squeeze film characteristics can be increased or decreased. Furthermore, results show that the surface roughness with circular pattern increases squeeze film characteristics, while the surface roughness with radial pattern will decrease it.
Originality/value
This paper is relatively original and describes the squeeze film characteristics between two parallel circular discs with ferro- fluid, rotational inertia, couple stresses and surface roughness effects.
Details
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Maghsood Daliri and Nader Javani
The purpose of this paper is to investigate squeezing motion between conical plates lubricated by ferro-fluid couple stress lubricants considering convective fluid inertia effects.
Abstract
Purpose
The purpose of this paper is to investigate squeezing motion between conical plates lubricated by ferro-fluid couple stress lubricants considering convective fluid inertia effects.
Design/methodology/approach
Based upon the Stokes couple stress theory, Ferro-hydrodynamic model of Shliomis and averaged inertia principle, squeeze film characteristics between conical plates are obtained.
Findings
According to the results, it is found that couple stress ferro-fluid lubricants increase squeeze film characteristics. Moreover, with increasing convective fluid inertia parameter, the squeeze film characteristics are increased. In contrast, the dimensionless load-carrying capacity diminishes when half cone angle of conical plate increases.
Originality/value
This paper is relatively original and it describes the squeeze film characteristics between conical plates with ferro-fluid, convective inertia, couple stresses and half cone angle of conical plate effects.
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Vishal Singh and Arvind K. Rajput
The present paper aims to analyse the synergistic effect of pocket orientation and piezo-viscous-polar (PVP) lubrication on the performance of multi-recessed hybrid journal…
Abstract
Purpose
The present paper aims to analyse the synergistic effect of pocket orientation and piezo-viscous-polar (PVP) lubrication on the performance of multi-recessed hybrid journal bearing (MHJB) system.
Design/methodology/approach
To simulate the behaviour of PVP lubricant in clearance space of the MHJB system, the modified form of Reynolds equation is numerically solved by using finite element method. Galerkin’s method is used to obtain the weak form of the governing equation. The system equation is solved by Gauss–Seidal iterative method to compute the unknown values of nodal oil film pressure. Subsequently, performance characteristics of bearing system are computed.
Findings
The simulated results reveal that the location of pressurised lubricant inlets significantly affects the oil film pressure distribution and may cause a significant effect on the characteristics of bearing system. Further, the use of PVP lubricant may significantly enhances the performance of the bearing system, namely.
Originality/value
The present work examines the influence of pocket orientation with respect to loading direction on the characteristics of PVP fluid lubricated MHJB system and provides vital information regarding the design of journal bearing system.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2023-0241/
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Nioosha Ghasemi Dolatsara, Maghsood Daliri and Moharram Shameli
The purpose of this paper is to investigate squeezing and rotating motions between two parallel annular discs lubricated by ferro-fluid couple stress lubricant in the presence of…
Abstract
Purpose
The purpose of this paper is to investigate squeezing and rotating motions between two parallel annular discs lubricated by ferro-fluid couple stress lubricant in the presence of a uniform magnetic field.
Design/methodology/approach
Based upon the Stokes couple stress theory and ferro-hydrodynamic model of Shliomis, squeeze film characteristics between two parallel annular discs are obtained.
Findings
According to the results, it is found that the combined effects of couple stress and ferro-fluid lubricant increase squeeze film performance with respect to the classical Newtonian lubricant. However, an increase in the rotational inertia parameter reduces squeeze film characteristics.
Originality/value
This paper is relatively original and describes the squeeze film characteristics between two parallel annular discs with rotational inertia, couple stress and ferro-fluid lubricant effects.
Details
Keywords
Sisi Wang, Dickson K. W. Chiu and Kevin K.W. Ho
With the widespread popularity of Esports, Esports game addiction has attracted wide attention. This research explores the causes of Esports game addiction among college students…
Abstract
Purpose
With the widespread popularity of Esports, Esports game addiction has attracted wide attention. This research explores the causes of Esports game addiction among college students in Mainland China and the influence of specific participation motivation and self-control on college students’ Esports game addiction.
Design/methodology/approach
This research applied the organismic integration theory (OIT) instead of the basic psychological needs theory using Honor of Kings, the most popular Esports game in the form of multiplayer online battle arena (MOBA) among Chinese college students. A total of 339 completed questionnaires were finally analyzed. SmartPLS 2.0 M3 was used to perform the PLS-SEM analysis on the relationship between self-control, participation motivation and Esports game addiction.
Findings
Only introjected regulation and a motivation positively impacted Esports game addiction, while intrinsic motivation, integrated regulation, identified regulation and external regulation had surprisingly no effect on Esports game addiction.
Originality/value
Scant studies have explored Esports game addiction in MOBA games, especially in Asia. Results showed that parents, schools and society should consciously strengthen the education and exercise of students’ self-control ability to prevent Esports game addiction. Game developers should appropriately adjust game structures and functions to prevent college students from using them as social tools or games to escape reality.
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Keywords
Khalil Atlassi, Mohamed Nabhani and Mohamed El Khlifi
This study aims to investigate the combined effects of roughness and ferrofluid lubricant on finite journal bearing load capacity and squeeze time.
Abstract
Purpose
This study aims to investigate the combined effects of roughness and ferrofluid lubricant on finite journal bearing load capacity and squeeze time.
Design/methodology/approach
The stochastic theory of Christensen is applied to study the surface roughness effect. The Shliomis model is used to take into account the effects of the rotational viscosity of ferromagnetic particles and their magnetic moment. A finite wire located in the center of the shaft produces the applied magnetic field. A developed computing code allows predicting the effect of the surface roughness on the performance of the considered journal bearing. The good agreement with the results of the literature validates the used approach.
Findings
This study shows that unlike longitudinal roughness, the presence of transverse roughness makes the use of ferrofluid more beneficial in terms of increasing the performance of finite journal bearings. This increase is more significant for large relative eccentricities, which present an ideal confinement.
Originality/value
This study shows the effect of two surface roughness patterns on the squeezing performance of a finite journal bearing lubricated by a ferrofluid.
Details
Keywords
Syed Haroon Abdul Gafoor and Padma Theagarajan
Conventional diagnostic techniques, on the other hand, may be prone to subjectivity since they depend on assessment of motions that are often subtle to individual eyes and hence…
Abstract
Purpose
Conventional diagnostic techniques, on the other hand, may be prone to subjectivity since they depend on assessment of motions that are often subtle to individual eyes and hence hard to classify, potentially resulting in misdiagnosis. Meanwhile, early nonmotor signs of Parkinson’s disease (PD) can be mild and may be due to variety of other conditions. As a result, these signs are usually ignored, making early PD diagnosis difficult. Machine learning approaches for PD classification and healthy controls or individuals with similar medical symptoms have been introduced to solve these problems and to enhance the diagnostic and assessment processes of PD (like, movement disorders or other Parkinsonian syndromes).
Design/methodology/approach
Medical observations and evaluation of medical symptoms, including characterization of a wide range of motor indications, are commonly used to diagnose PD. The quantity of the data being processed has grown in the last five years; feature selection has become a prerequisite before any classification. This study introduces a feature selection method based on the score-based artificial fish swarm algorithm (SAFSA) to overcome this issue.
Findings
This study adds to the accuracy of PD identification by reducing the amount of chosen vocal features while to use the most recent and largest publicly accessible database. Feature subset selection in PD detection techniques starts by eliminating features that are not relevant or redundant. According to a few objective functions, features subset chosen should provide the best performance.
Research limitations/implications
In many situations, this is an Nondeterministic Polynomial Time (NP-Hard) issue. This method enhances the PD detection rate by selecting the most essential features from the database. To begin, the data set's dimensionality is reduced using Singular Value Decomposition dimensionality technique. Next, Biogeography-Based Optimization (BBO) for feature selection; the weight value is a vital parameter for finding the best features in PD classification.
Originality/value
PD classification is done by using ensemble learning classification approaches such as hybrid classifier of fuzzy K-nearest neighbor, kernel support vector machines, fuzzy convolutional neural network and random forest. The suggested classifiers are trained using data from UCI ML repository, and their results are verified using leave-one-person-out cross validation. The measures employed to assess the classifier efficiency include accuracy, F-measure, Matthews correlation coefficient.
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Globally, consumer’s inclination towards functional foods had noticed due to their greater health consciousness coupled with enhanced health-care cost. The fact that probiotics…
Abstract
Purpose
Globally, consumer’s inclination towards functional foods had noticed due to their greater health consciousness coupled with enhanced health-care cost. The fact that probiotics could promote a healthier gut microbiome led projection of probiotic foods as functional foods and had emerged as an important dietary strategy for improved human health. It had established that ice cream was a better carrier for probiotics than fermented milked due to greater stability of probiotics in ice cream matrix. Global demand for ice cream boomed and probiotic ice cream could have been one of the most demanded functional foods. The purpose of this paper was to review the technological aspects and factors affecting probiotic viability and to standardize methodology to produce functional probiotic ice cream.
Design/methodology/approach
Attempt was made to search the literature (review and researched papers) to identify diverse factors affecting the probiotic viability and major technological challenge faced during formulation of probiotic ice cream. Keywords used for data searched included dairy-based functional foods, ice cream variants, probiotic ice cream, factors affecting probiotic viability and health benefits of probiotic ice cream.
Findings
Retention of probiotic viability at a level of >106 cfu/ml is a prerequisite for functional probiotic ice creams. Functional probiotic ice cream could have been produced with the modification of basic mix and modulating technological parameters during processing and freezing. Functionality can be further enhanced with the inclusion of certain nutraceutical components such as prebiotics, antioxidant, phenolic compounds and dietary fibres. Based upon reviewed literature, suggested method for the manufacture of functional probiotic ice cream involved freezing of a probiotic ice cream mix obtained by blending 10% probiotic fermented milk with 90% non-fermented plain ice cream mix for higher probiotic viability. Probiotic ice cream with functional features, comparable with traditional ice cream in terms of technological and sensory properties could be produced and can crop up as a novel functional food.
Originality/value
Probiotic ice cream with functional features may attract food manufacturers to cater health-conscious consumers.
Details
Keywords
Hadi Dehbovid, Habib Adarang and Mohammad Bagher Tavakoli
Charge pump phase locked loops (CPPLLs) are nonlinear systems as a result of the nonlinear behavior of voltage-controlled oscillators (VCO). This paper aims to specify jitter…
Abstract
Purpose
Charge pump phase locked loops (CPPLLs) are nonlinear systems as a result of the nonlinear behavior of voltage-controlled oscillators (VCO). This paper aims to specify jitter generation of voltage controlled oscillator phase noise in CPPLLs, by considering approximated practical model for VCO.
Design/methodology/approach
CPPLL, in practice, shows nonlinear behavior, and usually in LC-VCOs, it follows second-degree polynomial function behavior. Therefore, the nonlinear differential equation of the system is obtained which shows the CPPLLs are a nonlinear system with memory, and that Volterra series expansion is useful for such systems.
Findings
In this paper, by considering approximated practical model for VCO, jitter generation of voltage controlled oscillator phase noise in CPPLLs is specified. Behavioral simulation is used to validate the analytical results. The results show a suitable agreement between analytical equations and simulation results.
Originality/value
The proposed method in this paper has two advantages over the conventional design and analysis methods. First, in contrast to an ideal CPPLL, in which the characteristic of the VCO’s output frequency based on the control voltage is linear, in the present paper, a nonlinear behavior was considered for this characteristic in accordance with the real situations. Besides, regarding the simulations in this paper, a behavior similar to the second-degree polynomial was considered, which caused the dependence of the produced jitter’s characteristic corner frequency on the jitter’s amplitude. Second, some new nonlinear differential equations were proposed for the system, which ensured the calculation of the produced jitter of the VCO phase noise in CPPLLs. The presented method is general enough to be used for designing the CPPLL.