International Journal of Instrumentation Technology (4 papers in press)

Regular Issues

• A Novel Frequency Shifted Active Radar for Local Position Measurement of Rail Borne Vehicles for Industrial Conditions  
  by Prabal Patra, Chitresh Kundu, Arunangshu Ghosh, Bipan Tudu, Rajib Bandyopadhyay, Punit Rathore 
  Abstract: This paper presents active radar based position measurement system for rail borne vehicles. Laser systems are more accurate but fail to perform well in the dusty environment and also due to erroneous alignment. Conventional radar systems are rugged but prone to false echoes from various surrounding metallic structures which are always present in the industrial site. This affects radar based system adversely and the range gets limited to $50$m. To overcome this drawback, an active radar based system with frequency shift has been designed and developed which is suitable for industrial conditions and is used in positioning requirements of rail borne vehicles. The proposed system measures distance using return time of flight (RTOF) method. The echo signal is an active signal, generated by the slave to measure distance with very high precision and accuracy. The distance between the stations can be accurately determined over a range of 300 meters using this method with the accuracy of $pm 50$mm.
  Keywords: Radar; RTOF; Microstrip; Laser; Filter; Antenna.
  
  
• An overview of methods used for outdoor performance characterization of photovoltaic module string upto 10 kWp  
  by Javed Sayyad, Paresh Nasikkar 
  Abstract: Solar photovoltaic (SPV) energy is most promising among renewable energy (RE) sources. Outdoor performance characterization of SPV module string using on-field test equipment with a minimum error by reducing the effect of an uncertain operating condition (OPC) is challenging. Improving PV system reliability, flexibility and reducing operation and maintenance (O&M) cost have become a significant factor in increasing the competitiveness of the PV energy market. An illustrative embodiment of literature described herein is particularly suited to select load for current-voltage curve tracer (IVCT) for varying complexities from SPV cell (few Watts) to SPV module string (up to 10 kWp).
  Keywords: Current-voltage characteristics; Power-voltage characteristics; I-V curve tracer; PV string measurement; Performance monitoring; Photovoltaic module string.
  DOI: 10.1504/IJIT.2018.10018190
   
  
• Real time measurement of acidity and conductivity in rainwater  
  by Ruwan Weerasinghe, Ananda Pannila, Kithsiri Jayananda, Upul Sonnadara 
  Abstract: To monitor the acidity of rainwater, an automated rain sampler which can measure real-time pH level and conductivity of rainwater was developed and utilized during the southwest monsoon season. The rainwater sampler detects a start of a rain and collects a 250 ml of rainwater. The pH and the conductivity of the collected rainwater samples are measured and recorded together with the prevailing weather parameters. The pH probe is subjected to a verification test using standard buffer solution whereas the conductivity probe reading is verified using distilled water. The pH and conductivity measurements including weather data are transmitted to a remote location using a GSM modem for further analysis. A programmable logic controller is used to control entire process. Using the instrument, field measurements were carried out in Kandy in the hill country of Sri Lanka during the months from May to mid September. We conclude from the measurements that there are no apparent changes in the acidity in the rainwater during the southwest monsoon season and the instrument can be used successfully for environment monitoring in real time.
  Keywords: Conductivity; pH; Remote monitoring; Rainfall; Acid rain.
  
  
• Design and Development of Dry Microneedles Electrode Based Portable Wireless Instrumentation System for EEG Acquisition  
  by HARIKRISHNA SATISH THOTA 
  Abstract: A polymer dry microneedles electrode (DME) based portable multi-channel wireless electroencephalogram (EEG) acquisition system was developed in this work. The DME and its electronics were developed as an alternative acquisition methodology to the conventional wet electrode method, which requires skin preparation and application of gels to reduce the skinelectrode contact impedance. In order to overcome the aforesaid issues, dry microneedles electrodes were micromachined of size with base diameter 120 μm, tip diameter ranging between 5-10 μm and height 180-200 μm using biocompatible polymer, polymethyl methacrylate (PMMA) pellet and coated with metallic and metal nitride films to a total deposited film thickness ranging between 800-850 nm, those were both biocompatible and conductive. The proposed instrumentation system includes an EEG sensing circuitry comprising filters, amplifiers, an analog processing unit, a digital signal processing circuit comprising microcontroller and a Bluetooth wireless transmission module for loss-free signal transmission preventing signal distortion and cable noise. The developed electrodes were characterized for their electrical properties to acquire EEG signals from the frontal lobe of the brain. The performance of the developed electrodes was evaluated with respect to conventional wet electrodes using developed wireless instrumentation system and found that the amplitude and frequency response of both electrode systems had an average correlation and coherence of more than 90% proving that DME could be a futuristic alternative to conventional EEG acquisition systems.
  Keywords: Dry Microneedles Electrode; Electroencephalogram; Wireless Instrumentation; Skin Electrode Impedance; Signal Correlation & Coherence.