Siva Sankara Rao Yemineni, Mallikarjuna Rao Kutchibotla and Subba Rao V.V.
This paper aims to analyze deeply the effect of surface roughness conditions of the common interface of the two-layered riveted cantilever beams on their frictional damping during…
Abstract
Purpose
This paper aims to analyze deeply the effect of surface roughness conditions of the common interface of the two-layered riveted cantilever beams on their frictional damping during free lateral vibration at first mode. Here, the product, (µ × α), and damping ratio, ξ, are the parameters whose variations are analyzed in this investigation. For this, the influencing parameters considered are the natural frequency of vibration, f; the amplitude of initial excitation, y; and surface roughness value, Ra.
Design/methodology/approach
For experimentally evaluating logarithmic damping decrement, d, the frequency response function analyzer for the case of free lateral vibrations was used. Later, for evaluating the product, µ × α (where µ is the kinematic coefficient of friction and α is the dynamic slip ratio), and then, the damping ratio, ξ, the empirical relation suggested for logarithmic damping decrement, d, of riveted cantilever beams was used. After this, the full and reduced quadratic models of the product, µ × α, ξ, response surface methodology (RSM) with the help of Design Expert 11 software was used. Corresponding main effects plots, surface plots and prediction comparison plots were obtained to observe the variations of the product, µ × α, ξ for the variations of influencing parameters: f, y and Ra. Finally, a machine learning technique such as artificial neural networks (ANNs) using “nntool” present in MATLAB R13a software was used to predict the ξ for the different combinations of f, y and Ra.
Findings
The full and reduced quadratic regression models for the product, (µ × α) and the damping ratio, ξ of riveted cantilever beams for free lateral vibrations of the first mode in terms of the parameters: f, y and Ra were obtained. In addition, the main effects plots, surface plots and prediction comparison plots for the product, µ × α, ξ, with the corresponding experimental values of the product, µ × α, ξ, were obtained. Also, the execution of ANNs using MATLAB R13a software is proved to be the more accurate tool for the prediction of damping ratios in comparison to quadratic regression equations obtained from Design Expert 11 software. In the end, the assumption that the effect of surface roughness value on the product, (µ × α), and the damping ratio, ξ, is negligible is proved to be true using the main effects plots for the product, (µ × α) and ξ obtained from the Design Expert 11 software.
Originality/value
Obtaining the full and reduced quadratic regression equations for the product, (µ × α), and ξ of the two-layered riveted cantilever beams in terms of parameters: f, y and Ra was done. In addition, the conditions for the corresponding minimum and maximum values of the product, (µ × α), and ξ were obtained. Later, the main effects plots, surface plots and comparison plots of the predicted product, (µ × α), and ξ versus experimental product, (µ × α), and ξ were also obtained. Finally, the predicted values of the product, (µ × α), and ξ using the ANNs tool are observed to be the more accurate values in comparison to that obtained from RSM using the Design Expert 11 software.
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Y. Srinivasa Rao and M. Satyam
The effects of material parameters and processing conditions on the resistance drop by high voltage discharge in PVC – graphite thick film resistors are studied in this paper. The…
Abstract
The effects of material parameters and processing conditions on the resistance drop by high voltage discharge in PVC – graphite thick film resistors are studied in this paper. The resistance drop increased upon an increase in graphite aggregate size, which is a function of material parameters and processing conditions. The resistance drop has been attributed to the dielectrophoretic motion of graphite particles in PVC by the application of high voltages to polymer thick film resistors.
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This paper elicits information, an excess of information and the stakeholders’ role in the use of information. The purpose of this paper is to create a “C5 model” (clients…
Abstract
Purpose
This paper elicits information, an excess of information and the stakeholders’ role in the use of information. The purpose of this paper is to create a “C5 model” (clients, connectivity, content, copyright and cost) for the consortium management to support and improve its academic and administrative decision-making skills and optimize returns.
Design/methodology/approach
The methodology used for this study was “strength, weakness, opportunity and threat” (SWOT) analysis. As a tool, it was used as one of the strategic analytical techniques to evaluate various aspects of consortium management. The purpose of choosing this method was to derive a set of strategies for comparing the internal (strengths/weaknesses) and external (opportunities/threats) forces of the “C5 model” of consortium management.
Findings
From the SWOT analysis of the “C5 model,” it was observed that four combinations, maxi-maxi (strengths/opportunities (SO), mini-maxi (weaknesses/opportunities (WO), maxi-mini (strengths/threats (ST)) and mini-mini (weaknesses/threats (WT)), were drawn to derive a set of strategies to benefit the consortium management. The SO strategies such as building a client-centric resource management system, centralized gateway, collaborative acquisition model, common copyright communication and clearance center and cost-benefit analysis were built on the basis of the strengths and opportunities identified. Likewise, the WO strategies such as organizational planning, equality in ICT infrastructure facilities, quality content, public disclosure of copyright obligations and effective economic models were drawn to minimize the weaknesses of each component by taking advantage of the identified opportunities. The ST strategies were worked out using strengths of the model to possibly mitigate its threats. Similarly, the WT strategies were created to minimize the weaknesses and avoid the threats as much as possible. However, these strategies would not only help consortium management in the decision-making process, but also optimize returns and improve the intellectual outcome of organizations.
Originality/value
Not many research studies have been developed regarding the SWOT analysis of the “C5 model” for consortium management. This study attempts to benefit a large community of library and information science professionals, consortia and their clients.
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Busi Rambabu and Y. Srinivasa Rao
The purpose of this paper is to study high-voltage interactions in polymer thick-film resistors, namely, polyvinyl chloride (PVC)-graphite thick-film resistors, and their…
Abstract
Purpose
The purpose of this paper is to study high-voltage interactions in polymer thick-film resistors, namely, polyvinyl chloride (PVC)-graphite thick-film resistors, and their applications in universal trimming of these resistors.
Design/methodology/approach
The authors applied high voltages in the form of pulses and impulses of various pulse durations and with different amplitudes to polymer thick-film resistors and observed the variation of resistance of these resistors with high voltages.
Findings
The paper finds that high voltages can be used for trimming of polymer thick-film resistors in both directions, i.e. upwards and downwards.
Research limitations/implications
The research implication of this paper is that polymer thick-film resistors can be trimmed downwards or upwards practically using this method.
Practical implications
The practical implications of this paper is that one can trim the polymer thick-film resistors, namely, PVC–graphite thick-film resistors, in both directions, i.e. upwards and downwards, by using this method.
Originality/value
The value of the paper is in showing that high voltages can be used to trim downwards and also upwards in the case of polymer thick-film resistors. This type of trimming is called universal trimming, developed first time for polymer thick-film resistors.
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Y. Srinivasa Rao and M. Satyam
This paper deals with the investigations carried out on the variation of current noise (1/f noise) in polymer thick film resistors, when they are subjected to pulse voltage…
Abstract
This paper deals with the investigations carried out on the variation of current noise (1/f noise) in polymer thick film resistors, when they are subjected to pulse voltage trimming. The current noise is measured in terms of noise index (micro volts of noise per volt of DC applied, in a decade of frequency) using Noise Meter Model 315 C manufactured by Quan‐Tech of New Jersey. It has been found that current noise decreases as the resistors are trimmed to lower values. An attempt has been made to explain the decrease in current noise with the trimming of resistors.
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The purpose of this paper is to study the variation of the temperature coefficient of resistance (TCR) of polymer thick film resistors, namely, PVC‐graphite thick film resistors…
Abstract
Purpose
The purpose of this paper is to study the variation of the temperature coefficient of resistance (TCR) of polymer thick film resistors, namely, PVC‐graphite thick film resistors, with parameters such as volume fraction, grain size, and high voltage.
Design/methodology/approach
A model is proposed to explain the observed variations, which assumes that the texture of the thick film resistors consists of insulator granules coated with conducting particles.
Findings
The paper finds that the TCR of these materials is controlled mainly by the contact resistance fluctuations between the conducting particles and the number of contacts each particle has with it neighbours. The variation of TCR with high voltage has also been explained with the help of this model and it is attributed to the changes in contact area and the number of contacts.
Originality/value
The value of the paper is in showing that apparently the TCR of polymer thick film resistors can be controlled by the expansion properties of the insulating medium. The variation of TCR with high voltage is also due to change in number of contacts between the conducting particles. These types of material may find applications in thermal sensors or as temperature control elements.
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In this study, it is aimed to develop cooling models for the efficient use of batteries and to show how important the busbar material is. Batteries, which are indispensable energy…
Abstract
Purpose
In this study, it is aimed to develop cooling models for the efficient use of batteries and to show how important the busbar material is. Batteries, which are indispensable energy sources of electric aircraft, automobiles and portable devices, may eventually run out. Battery life decreases over time; the most critical factor is temperature. The temperature of batteries should not exceed the safe operating temperature of 313 K and it is recommended to have a balanced temperature distribution through the battery.
Design/methodology/approach
In this study, the effect on the battery temperature caused by using different busbar materials to connect batteries together was investigated. Gold, copper and titanium were chosen as the different busbar material. The Air velocities used were 1 m/s and 2 m/s, the air inlet temperatures were 295 and 300 K and the discharge rates 1.0–1.5–2.0–2.5C were chosen for cooling the batteries.
Findings
The best busbar material was identified as copper. Because these studies are long-term studies, it is also suggested to estimate the data obtained with ANN (Artificial Neural Networks). The purpose of ANN is to enable the solution of many different complex problems by creating systems that do not require human intelligence. Four different program (BR-LM-CGP-SCG) were used to estimate the data obtained with ANN. It was found that the most reliable algorithm was BR18. The R2 size of the BR18 algorithm in the test phase was 0.999552, the CoV size was 0.007697 and the RMSE size was 0.005076.
Originality/value
When the literature is considered, the cooling part of the battery modules has been taken into consideration during the temperature observation of the battery modules, but busbar materials connecting the batteries have always been ignored. In this study, various busbar materials were used and it was noticed how the temperature of the battery model changed under the same working conditions. These studies are very time-consuming and costly studies. Therefore, an estimation of the data obtained with artificial neural networks (ANN) was also evaluated.
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Y. Srinivasa Rao and M. Satyam
The effect of high voltage pulses on the resistance of polymer thick film resistors (PTFR) is studied. It is found that the resistance decreases with both the amplitude and…
Abstract
The effect of high voltage pulses on the resistance of polymer thick film resistors (PTFR) is studied. It is found that the resistance decreases with both the amplitude and duration of the high voltage pulses and with the number of pulses. The change in resistance is attributed to the dielectrophoretic motion of graphite granules in the PVC medium when high voltage pulses are applied to PTFR. A model has been proposed through which the percentage change in resistance can be estimated in terms of the number of pulses, duration of pulses etc. Based on these investigations, we suggest a downward trimming method for PTFR through the application of high voltage pulses. This method of trimming is a clean process and trimmed resistors are free from hot spots.
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Kandagaddla Venkatasubrahmanayam, Busi Ram Babu, Billa Poornaiah and Yarravarapu Srinivasa Rao
The purpose of this paper is to study the microwave interactions in polymer thick film resistors, namely, polyvinyl chloride (PVC)-graphite thick film resistors, and its…
Abstract
Purpose
The purpose of this paper is to study the microwave interactions in polymer thick film resistors, namely, polyvinyl chloride (PVC)-graphite thick film resistors, and its applications in trimming of these resistors.
Design/methodology/approach
We applied microwave radiation in the form of pulses of various pulse durations and with different powers to polymer thick film resistors and observed the variation of resistance of these resistors with microwave radiation.
Findings
The paper finds that microwave radiation can be used for trimming of polymer thick film resistors.
Research limitations/implications
The research implication of this paper is that polymer thick film resistors can be trimmed practically using this method.
Practical implications
The practical implication of this paper is that we can trim the polymer thick film resistors, namely, PVC-graphite thick film resistor, by using this method.
Originality/value
The value of the paper is in showing that microwave radiation can be used to trim downwards in the case of high-value resistors and trim upwards in the case of low-value resistors.