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1 – 6 of 6Gobi K., Kannapiran B., Devaraj D. and Valarmathi K.
The conventional strain gauge type pressure sensor suffers in static testing of engines due to the contact transduction method. This paper aims to focus on the concept of…
Abstract
Purpose
The conventional strain gauge type pressure sensor suffers in static testing of engines due to the contact transduction method. This paper aims to focus on the concept of non-contact transduction-based pressure sensor using eddy current displacement sensing coil (ECDS) to overcome the temperature limitations of the strain gauge type pressure sensor. This paper includes the fabrication of prototypes of the proposed pressure sensor and its performance evaluation by static calibration. The fabricated pressure sensor is proposed to measure pressure in static test environment for a short period in the order of few seconds. The limitations of the fabricated pressure sensor related to temperature problems are highlighted and the suitable design changes are recommended to aid the future design.
Design/methodology/approach
The design of ECDS-based pressure sensor is aimed to provide non-contact transduction to overcome the limitations of the strain gauge type of pressure sensor. The ECDS is designed and fabricated with two configurations to measure deflection of the diaphragm corresponding to the applied pressure. The fabricated ECDS is calibrated using a standard micro meter to ensure transduction within limits. The fabricated prototypes of pressure sensors are calibrated using dead weight tester, and the calibration results are analyzed to select the best configuration. The proposed pressure sensor is tested at different temperatures, and the test results are analyzed to provide recommendations to overcome the shortcomings.
Findings
The performance of the different configurations of the pressure sensor using ECDS is evaluated using the calibration data. The analysis of the calibration results indicates that the pressure sensor using ECDS (coil-B) with the diaphragm as target is the best configuration. The accuracy of the fabricated pressure sensor with best configuration is ±2.8 per cent and the full scale (FS) output is 3.8 KHz. The designed non-contact transduction method extends the operating temperature of the pressure sensor up to 150°C with the specified accuracy for the short period.
Originality/value
Most studies of eddy current sensing coil focus on the displacement and position measurement but not on the pressure measurement. This paper is concerned with the design of the pressure sensor using ECDS to realize the non-contact transduction to overcome the limitations of strain gauge type pressure sensors and evaluation of the fabricated prototypes. It is shown that the accuracy of the proposed pressure sensor is not affected by the high temperature for the short period due to non-contact transduction using ECDS.
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K. Gobi, B. Kannapiran, D. Devaraj and K. Valarmathi
In Aerospace applications, the inlet tubes are used to mount strain gauge type pressure sensors on the engine under static test to measure engine chamber pressure. This paper aims…
Abstract
Purpose
In Aerospace applications, the inlet tubes are used to mount strain gauge type pressure sensors on the engine under static test to measure engine chamber pressure. This paper aims to focus on the limitations of the inlet tube and its design aspects to serve better in the static test environment. The different sizes of the inlet tubes are designed to meet the static test and safety requirements. This paper presents the performance evaluation of the designed inlet tubes with calibration results and the selection criteria of the inlet tube to measure combustion chamber pressure with the specified accuracy during static testing of engines.
Design/methodology/approach
Two sensors, specifically, one cavity type pressure sensor with the inlet tube of range 0-6.89 MPa having natural frequency of the diaphragm 17 KHz and another flush diaphragm type pressure sensor of the same range having −3 dB frequency response, 5 KHz are mounted on the same pressure port of the engine under static test to study the shortcomings of the inlet tube. The limitations of the inlet tube have been analyzed to aid the tube design. The different sizes of inlet tubes are designed, fabricated and tested to study the effect of the inlet tube on the performance of the pressure sensor. The dynamic calibration is used for this purpose. The dynamic parameters of the sensor with the designed tubes are calculated and analyzed to meet the static test requirements. The diaphragm temperature test is conducted on the representative hardware of pressure sensor with and without inlet tube to analyze the effect of the inlet tube against the temperature error. The inlet tube design is validated through the static test to gain confidence on measurement.
Findings
The cavity type pressure sensor failed to capture the pressure peak, whereas the flush diaphragm type pressure sensor captured the pressure peak of the engine under a static test. From the static test data and dynamic calibration results, the bandwidth of cavity type sensor with tube is much lower than the required bandwidth (five times the bandwidth of the measurand), and hence, the cavity type sensor did not capture the pressure peak data. The dynamic calibration results of the pressure sensor with and without an inlet tube show that the reduction of the bandwidth of the pressure sensor is mainly due to the inlet tube. From the analysis of dynamic calibration results of the sensor with the designed inlet tubes of different sizes, it is shown that the bandwidth of the pressure sensor decreases as the tube length increases. The bandwidth of the pressure sensor with tube increases as the tube inner diameter increases. The tube with a larger diameter leads to a mounting problem. The inlet tube of dimensions 6 × 4 × 50 mm is selected as it helps to overcome the mounting problem with the required bandwidth. From the static test data acquired using the pressure sensor with the selected inlet tube, it is shown that the selected tube aids the sensor to measure the pressure peak accurately. The designed inlet tube limits the diaphragm temperature within the compensated temperature of the sensor for 5.2 s from the firing of the engine.
Originality/value
Most studies of pressure sensor focus on the design of a sensor to measure static and slow varying pressure, but not on the transient pressure measurement and the design of the inlet tube. This paper presents the limitations of the inlet tube against the bandwidth requirement and recommends dynamic calibration of the sensor to evaluate the bandwidth of the sensor with the inlet tube. In this paper, the design aspects of the inlet tube and its effect on the bandwidth of the pressure sensor and the temperature error of the measured pressure values are presented with experimental results. The calibration results of the inlet tubes with different configurations are analyzed to select the best geometry of the tube and the selected tube is validated in the static test environment.
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Nabil Moukafih, Ghizlane Orhanou and Said Elhajji
This paper aims to propose a mobile agent-based security information and event management architecture (MA-SIEM) that uses mobile agents for near real-time event collection and…
Abstract
Purpose
This paper aims to propose a mobile agent-based security information and event management architecture (MA-SIEM) that uses mobile agents for near real-time event collection and normalization on the source device. The externalization of the normalization process, executed by several distributed mobile agents on interconnected computers and devices, proposes a SIEM server dedicated mainly for correlation and analysis.
Design/methodology/approach
The architecture has been proposed in three stages. In the first step, the authors described the different aspects of the proposed approach. Then they implemented the proposed architecture and presented a new vision for the insertion of normalized data into the SIEM database. Finally, the authors performed a numerical comparison between the approach used in the proposed architecture and that of existing SIEM systems.
Findings
The results of the experiments showed that MA-SIEM systems are more efficient than existing SIEM systems because they leave the SIEM resources primarily dedicated to advanced correlation analysis. In addition, this paper takes into account realistic scenarios and use-cases and proposes a fully automated process for transferring normalized events in near real time to the SIEM server for further analysis using mobile agents.
Originality/value
The work provides new insights into the normalization security-related events using light mobile agents.
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Rup Singh and Saten Kumar
The purpose of this paper is to analyze narrow money demand functions for the Pacific Island countries (PICs) and evaluate their stability. The selected PICs are Fiji, Vanuatu…
Abstract
Purpose
The purpose of this paper is to analyze narrow money demand functions for the Pacific Island countries (PICs) and evaluate their stability. The selected PICs are Fiji, Vanuatu, Samoa (SAM), Solomons and the Papua New Guinea. The stability of the demand for money is vital for the formulation of the monetary policy.
Design/methodology/approach
The augmented Dicky‐Fuller method is employed to test the time series properties of the variables. Alternative time series techniques such as general to specific (GETS) and Johansen maximum likelihood (JML) are used with annual data from 1974 to 2004 (except for SAM with data from 1980 to 2004) to estimate the narrow money demand equations. To draw inferences relative to the stability of the parameters, the study applies the cumulative recursive sum of recursive residuals (CUSUM) and the cumulative sum of squares of recursive residuals (CUSUMSQ).
Findings
The results from the time series approaches of GETS and JML suggest that real income, nominal rate of interest and real narrow money are cointegrated. The CUSUM and CUSUMSQ stability test results indicate that the demand for money functions for these countries are stable and, therefore, the respective monetary authorities may consider targeting money supply in their conduct of monetary policy. It is argued that the financial sector reforms and liberalization is yet to have any significant effects on the money demand in the PICs.
Research limitations/implications
The methods of estimation does not allow for structural breaks in the cointegrating relationship. It is hoped that future research may focus on using the structural break techniques and also investigate the stability of the demand for broad money in the PICs. Further due to limitations in the data, the authors were only able to select five PICs.
Originality/value
This is the first paper in the literature that provides long‐run estimates and stability results of the narrow money demand using the newest time series techniques for a group of PICs over the period 1974‐2004.
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Seema Narayan and Russell Smyth
The purpose of this paper is to examine the time series properties of 26 macroeconomic variables in Papua New Guinea (PNG) over the period 1970‐2006.
Abstract
Purpose
The purpose of this paper is to examine the time series properties of 26 macroeconomic variables in Papua New Guinea (PNG) over the period 1970‐2006.
Design/methodology/approach
Both unit root and stationarity tests without a structural break and the Lagrange Multiplier (LM) unit root test with one and two structural breaks developed by Lee and Strazicich are applied to each of the 26 macroeconomic variables in PNG. Compared to popular ADF‐type endogenous unit root tests such as those proposed by Zivot and Andrews and Lumsdaine and Papell, the LM unit root test with one and two structural breaks has the advantage that it is unaffected by breaks under the null.
Findings
The unit root and stationarity tests without structural breaks find at best mixed evidence of mean reversion and/or trend reversion for most variables. This result is likely to reflect the failure of these tests to allow for structural breaks, given the power to find stationarity declines if the data contain a structural break that is ignored. When the LM unit root test with one and two structural breaks is applied, it is found that at least 23 of the 26 macroeconomic variables are trend stationary.
Originality/value
The time series properties of macroeconomic variables have important implications for several macroeconomic theories. There are, however, few studies of the time series properties of macroeconomic variables in developing countries and no comprehensive studies for any of the Pacific Island countries. This paper begins to fill this gap as the first to provide a systematic examination of the time series properties of macroeconomic variables in Paua New Guinea.
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Adah-Kole Emmanuel Onjewu, Arun Sukumar, K. V. D. Prakash and Mohamed Yacine Haddoud
Based on a single case approach, this chapter empirically explores the triple helix configuration of Centurion University of Technology and Management (CUTM) and its social…
Abstract
Based on a single case approach, this chapter empirically explores the triple helix configuration of Centurion University of Technology and Management (CUTM) and its social innovation programme. The study uses case files and web available material to consider the nature of the university’s relationship with industry and government. The findings show that triple helix social innovation has yet to be studied in an Indian context. Also, CUTM’s human and social orientation is a driver of its triple helix interaction. The university’s pursuit and trust in employers’ participation in the curriculum and campus experience is the hallmark of its social and pedagogic success. To advance the literature, this chapter draws attention to a much-overlooked Indian context and, for practitioners, it demonstrates the inner-workings of a functioning triple helix system.
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