R. Raghavendra Rao and K. Raja Sekhar
This paper aims to study the effects of couple stresses and surface roughness on the minimum film thickness of heavily loaded rollers and to discuss these by following Grubin's…
Abstract
Purpose
This paper aims to study the effects of couple stresses and surface roughness on the minimum film thickness of heavily loaded rollers and to discuss these by following Grubin's approach and Crook's approximations.
Design/methodology/approach
A generalised form of Reynolds equation for rough surfaces with lubricant as couple stress fluid is derived. This equation is then used to study the combined effect of couple stresses and surface roughness on the roller bearings under heavily loaded conditions. EHD minimum film thickness expressions is obtained by following Grubin's approach and Crook's approximation and it is studied numerically.
Findings
It is found that, as the chain length of the additive molecules increases, the elastohydrodynamic minimum film thickness increases. Also, as the mean height of roughness asperities increases, the elastohydrodynamic minimum film thickness increases for the transversal roughness and it decreases in the case of longitudinal roughness.
Research limitations/implications
These effects are studied theoretically by the mathematical equations in heavily loaded roller bearings.
Practical implications
Reduction of the film thickness in the EHD lubrication between the rollers can be compensated by the use of lubricants containing additives of molecules of size. As a result the bearing performance can be improved.
Originality/value
This research paper provides a closed form of the expressions for the bearings in EHD lubrication and is studied with regard to couple stress parameter. This paper helps to manufacture better bearings.
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Sreedevi Gandluru, Prasada Rao D.R.V. and O.D. Makinde
The purpose of this paper is to investigate the impact of thermal radiation interaction with Hall current, buoyancy force, and oscillatory surface temperature on…
Abstract
Purpose
The purpose of this paper is to investigate the impact of thermal radiation interaction with Hall current, buoyancy force, and oscillatory surface temperature on hydromagnetic-mixed convective heat exchange stream of an electrically conducting nanofluid past a moving permeable plate in a porous medium within a rotating system.
Design/methodology/approach
Analytical closed-form solutions are obtained for both the momentum and the energy equations using the perturbation method.
Findings
The effects of various important parameters on velocity and temperature fields within the boundary layer are discussed for three different water-based nanofluids containing copper (Cu), aluminum oxide (Al2O3), and titanium dioxide (TiO2) as nanoparticles. Local skin friction and Nusselt number are illustrated graphically and discussed quantitatively. The results show that Hall current significantly affects the flow system. Results for some special cases of the present analysis are in good agreement with the existing literature.
Originality/value
The problem is relatively original to study the hydromagnetic-oscillatory flow of a nanofluid with Hall effect and thermal radiation past a vertical plate in a rotating porous medium.
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Raghavendra Rao N.S. and Chitra A.
The purpose of this study is to propose an extended reliability method for an industrial motor drive by integrating the physics of failure (PoF).
Abstract
Purpose
The purpose of this study is to propose an extended reliability method for an industrial motor drive by integrating the physics of failure (PoF).
Design/methodology/approach
Industrial motor drive systems (IMDS) are currently expected to perform beyond the desired operating conditions to meet the demand. The PoF of the subsystem affects its reliability under such harsh operating circumstances. It is crucial to estimate reliability by integrating PoF, which helps in understanding its impact and to develop a fault-tolerant design, particularly in such an integrated drive system. An integrated PoF extended reliability method for industrial drive system is proposed to address this issue. In research, the numerical failure rate of each component of industrial drive is obtained first with the help of the MIL-HDBK-217 military handbook. Furthermore, the mathematically deduced proposed approach is modeled in the GoldSim Monte Carlo reliability workbench.
Findings
From the results, for a 15% rise in integrated PoF, the reliability and availability of the entire IMDS dropped by 23%, resulting in an impact on mean time to failure (MTTF).
Originality/value
The integrated PoF of the motor and motor controller affects industrial drive reliability, which falls to 0.18 with the least MTTF (2.27 years); whose overall reliability of industrial drive drops to 0.06 if it is additionally integrated with communication protocol.
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Raghavendra Rao N.S. and Chitra A.
The purpose of this study is to extend a sensitivity-based reliability technique for the processors deployed in industrial drive (ID).
Abstract
Purpose
The purpose of this study is to extend a sensitivity-based reliability technique for the processors deployed in industrial drive (ID).
Design/methodology/approach
The processor provides flexible operation, re-configurability, and adaptable compatibility in industrial motor drive system. A sensitivity-based model allows a robust tool for validating the system design. Sensitivity is the probability of a partial failure rate for a distributed variable; sensitivity and failure rates are also complementary. Conversely, traditional power electronic components reliability estimating standards have overlooked it, and it is essential to update them to account for the sensitivity parameter. A new sensitivity-based reliability prediction methodology for a typical 32-bit microprocessor operating at 30ºC deployed in ID is presented to fill this gap. The proposed techniques are compared with the estimated processor reliability values obtained from various reliability standards using the validated advanced logistics development tool. The main contribution of this work is to provide a sensitivity extended reliability method over the conventional method directing toward improving reliability, availability, and maintainability in the design of ID.
Findings
The analysis shows that the sensitivity of the processor’s circuit increases due to increases in complexity of the system by reducing the overall mean time between failure upon comparing among conventional reliability standards.
Originality/value
The significance of this paper lies in the overall, sensitivity-based reliability technique for processors in comparison to the traditional reliability complexity in IDs.
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Basant Kumar Jha and Muhammad Nasir Sarki
The purpose of this paper is to conduct a theoretical study on steady fully developed non-linear natural convection and mass transfer flow past an infinite vertical moving porous…
Abstract
Purpose
The purpose of this paper is to conduct a theoretical study on steady fully developed non-linear natural convection and mass transfer flow past an infinite vertical moving porous plate with chemical reaction and thermal diffusion effect. Closed-form expressions for dimensionless velocity, concentration, Sherwood number and skin-friction are obtained by solving the present mathematical model.
Design/methodology/approach
The fully developed steady non-linear natural convection and mass transfer flow near a vertical moving porous plate with chemical reaction and thermal diffusion effect is investigated. The non-linear density variation and Soret effect were taken into consideration. The dimensionless velocity, temperature and concentration profiles were obtained in terms of exponential functions, and were used to compute the governing parameters, skin-friction and Sherwood number.
Findings
The effect of coefficient of the non-linear density variation with the temperature (NDT) and concentration (NDC) parameter, chemical reaction parameter, thermal diffusion parameter are discussed with the aid of line graphs and tables. The analysis of the result shows that the velocity as well as skin-friction having higher values in the case of non-linear variation of density with temperature and concentration in comparison to linear variation of density with temperature and concentration. It is observed that the velocity and skin-friction increase with an increase in the Soret parameter.
Originality/value
The aim of this paper is to extend the work of Muthucumaraswamy (2002) by incorporating the thermal diffusion (Soret) effect and non-linear density variation with temperature (NDT) and concentration (NDC), on which, to the best knowledge of the authors, no studies have been carried out.
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K. Thirugnanasambantham, Pillai K. Rajasekharan, Vidya Patwardhan, G. Raghavendra and Shreelatha Rao
India has a marvelous distinction of hosting religious and cultural extravaganzas on an enormous scale, keeping in with its rich lineage and civilizational assortment. The…
Abstract
Purpose
India has a marvelous distinction of hosting religious and cultural extravaganzas on an enormous scale, keeping in with its rich lineage and civilizational assortment. The philosophical threads of such festivals are eventually subjective well-being and spiritual awakening. In this context, the authors examine how the visitors' festival motivation culminates in life satisfaction and subjective well-being.
Design/methodology/approach
The study follows a theory-driven deductive approach to test the construed relationships. The data were collected from the sites of religious fiesta when the participants were immersed in their cultural fervor. The study uses structural equation modeling to examine the hypothesized model.
Findings
The study finds that place attachment and life satisfaction empirically mediate the relationship between festival motivation and subjective well-being. However, the relationship between place attachment and subjective well-being is not empirically strong when life satisfaction mediates their relationship.
Research limitations/implications
The study is based on a convenience sample and is limited to the visitors of local religious festivals. Future research must verify the suitability of the model in other types of festivals of other religions and different locations. Also, this research deliberates on the relationship between only four variables. Future researchers could discuss other variables such as authenticity, emotional solidarity, festival images, festival values, religious faith, etc. to develop a more robust model to explain the relationship between festival motivation and subjective well-being.
Practical implications
In India regardless of social strata, people are religiously conscious and inclined toward attending publicly celebrated religious festivals. The scale of these festivals is significant and given the scenario, the local Government has to join hands with the temple administration, local people and visitors to reap the full benefits of the festival. These temple festivals not only foster coordination and involvement among various stakeholders, but also invoke the devotion of the people to jointly organize the celebrations.
Social implications
As some of the religious festivals go beyond caste, creed and nationality, the celebrations should evolve as multi-cultural mass events uniting the societal cohesiveness, spirit and national culture. The variables chosen and results found in this study will surely support publicizing the significance of religious festivals in the region and provide an idea to the organizers and supporters to develop new strategies to promote similar events.
Originality/value
The results claim several implications for theory and practice. Theoretically, the study contributes to the literature on religious tourism and event management. Practically, the study discussions indicate the importance of disseminating the significance of religious festivals as a platform for local tourist attractions to generate social, cultural and economic benefits.
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The paper considers integral surfaces of systems of differential equations with impulse perturbations at fixed moments of time. Sufficient conditions have been obtained for the…
Abstract
The paper considers integral surfaces of systems of differential equations with impulse perturbations at fixed moments of time. Sufficient conditions have been obtained for the existence of integral surfaces with definite properties and the behaviour of the solutions has been studied with initial conditions outside these surfaces.
Saswati Tripathi, Siddhartha Shankar Roy and Bijoy Talukder
This paper analyses and assesses the effect of firm-specific determinants (FSDs) on supply-chain performance (SCP) and export performance (EP). It examines SCP’s influence on EP…
Abstract
Purpose
This paper analyses and assesses the effect of firm-specific determinants (FSDs) on supply-chain performance (SCP) and export performance (EP). It examines SCP’s influence on EP and its mediating effect on the relationship between FSD and EP.
Design/methodology/approach
This paper develops a theoretical framework based on the resource-based view (RBV) and dynamic-capability theory to understand SCP’s role in the FSD-EP link while empirically validating using the Indian automobile industry segments (IAIS) data. The sample frame comprises all listed firms in IAIS between the financial year 2010-11 and 2021–22, with continuous data availability throughout the considered timeline. The paper employs factor analysis for dimension reduction, a panel-data-fixed-effect model to analyze the relationships, bootstrap to test the mediation effect and focus-group discussion for validating the results obtained through statistical analyses.
Findings
FSD directly influences SCP’s efficiency aspect and EP. Distribution efficiency and inventory efficiency characteristics of SCP directly impact EP and completely mediate the relationship between FSD and EP.
Practical implications
This study provides significant insights into how firms can increase EP by focusing on firm-specific and SCP-related factors. To improve EP, firms should concentrate on enhancing distribution and inventory efficiencies. Firms must focus on critical firm-level factors like age, size and raw-material import capability to increase their ability to solve SC-specific barriers and improve SCP, resulting in enhanced exports.
Originality/value
This study investigates the impacts of FSD on SCP and EP and examines the mediating effect of SCP on the relationship between FSD and EP. Such a mediating role of SCP has rarely been probed in the literature.
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K. Nilakantan, Jayaram K. Sankaran and B.G. Raghavendra
The purpose of this paper is to construct a model of hierarchical manpower systems which follow proportionality policies in recruitment and promotion of their staff, ostensibly…
Abstract
Purpose
The purpose of this paper is to construct a model of hierarchical manpower systems which follow proportionality policies in recruitment and promotion of their staff, ostensibly with a view to safeguard the career interests of their existing employees.
Design/methodology/approach
The manpower systems are modeled as Markov systems, and their inherent characteristics and long‐term behavior are studied.
Findings
Significantly it is shown that such proportionality systems do not compromise on flexibility in the long term, and can also provide an additional means of controlling the blend of manpower in the system. The theoretical results were tested with real‐world data, and a good degree of conformity was observed between the theoretical predictions and the actually observed behaviour.
Practical implications
The model can also be applied to organizations which outsource a part of their work, the outsource workforce being notionally being considered as recruits to the system.
Originality/value
Outsourcing of work is being practiced on an ever‐increasing scale nowadays, and becoming, at times, even controversial, and as a consequence, an increasing number of organizations are resorting to protectionist policies; the model in this paper provides a theoretical framework in which to view and analyze this phenomenon.