Emerald | Sensor Review

Solar-powered sensors: a review of products and applications

Robert Bogue — 2012-03-23 00:00:00.0

Abstract

Purpose - This paper aims to review the technology and applications of solar-powered sensors. Design/methodology/approach - Following a short introduction, this paper firstly considers photovoltaic technology and then describes a selection of solar-powered sensors and their applications. Findings - This shows that solar-powered sensors may be used as nodes in wireless sensor networks and also as stand-alone devices. They offer a number of key operational and economic benefits and find applications in such diverse fields as structural and environmental monitoring, traffic management, weather forecasting, agriculture, process control, gas detection, satellite remote sensing and healthcare. Originality/value - This illustrates the important role that solar-powered sensors and systems play in a wide range of applications and industries.

Numerous Recent Shows Highlight the Latest in Sensor Innovations

Richard Bloss — 2012-03-23 00:00:00.0

Abstract

Purpose - Review of the Automate Show (vision and robotics), The Promat Show (material handling) that run jointly in Chicago plus review of the Sensor Expo with emphasis on the new sensor innovations and applications on displayDesign/methodology/approach - In-depth interviews with exhibitors of sensors of all types at these recent shows. Findings - Sensor suppliers have been busy applying wireless and energy harvesting technology to their devices. Vision suppliers continue to expand the capabilities of the video eye with 3D and other innovations. Research limitations/implications - Practical implications - System integrators and users have an ever growing array of new sensor technologies to answer previously tough application needs. Wireless sensors and innovative vision systems, including 3-D, offer new answers to material handling and other applications. MEMS commercialization development continues to drive ahead.Originality/value - Users and system integrators have an ever increasing range of innovative sensor solutions to help solve those previously difficult application requirements. For example, adding smart vision to logistic applications makes them faster, more accurate and more autonomous

Nanostructured Material Sensor Processing Using Microfabrication Techniques

2012-03-23 00:00:00.0

Abstract

Purpose - The development of chemical sensors based on nanostructures, such as nanotubes or nanowires, depends on the capability to reproducibly control the processing of the sensor. Alignment and consistent electrical contact of nanostructures on a microsensor platform is challenging. This can be accomplished using labor-intensive approaches, specialized processing technology, or growth of nanostructures in situ. However, the use of standard microfabrication techniques for fabricating nanostructured microsensors is problematic. This paper addresses this challenge using standard photoresist processing combined with dielectrophoresis. Design/methodology/approach - Nanostructures are suspended in photoresist and aligned between opposing sawtooth electrode patterns using an alternating current (AC) electric field (dielectrophoresis). The use of photoresist processing techniques allow the burying of the nanostructures between layers of metal, thus improving the electrical contact of the nanostructures to the microsensor platform. Findings - This approach is demonstrated for both multi-walled carbon nanotubes and tin oxide nanowires. Preliminary data shows the electrical continuity of the sensor structure as well as the response to various gases. Research limitations/implications - It is concluded that this approach demonstrates a foundation for a new tool for the fabrication of microsensors using nanostructures, and can be expanded towards enabling the combination of common microfabrication techniques with nanostructured sensor development. Originality/value - This approach is intended to address the significant barriers of deposition control, contact robustness, and simplified processing to realizing the potential of nanotechnology as applied to sensors.

Preparation and Characterization of the Solid-State Ag/AgCl Reference Electrode for RC Structures

Guofu Qiao, Huigang Xiao, Yi Hong, Yuelan Qiu — 2012-03-23 00:00:00.0

Abstract

Purpose - Corrosion sensors and networks are the most effective techniques to obtain the corrosion information and recognize the corrosion status of the reinforcing concrete structures. However, reference electrode is the key element to provide the baseline for potential control of the corrosion monitoring sensors during corrosion measurement process. Therefore, this paper aims to provide the novel solid-state reference electrode for the corrosion sensors.Design/methodology/approach - A solid-state Ag/AgCl reference electrode has been prepared. Furthermore, the performance of the reference electrode, such as stability, temperature response, anti-polarization and influence of the concrete admixture, has been investigated.Findings - The results indicate that the balance potential and the temperature coefficient of the reference electrode are 3.64 mv±1mv (vs. SCE) at 25? and -0.51 mv/?±0.03mv/?, respectively. Furthermore, the polarization curve exhibits characteristics of three stages as the polarization current is in [-10µA/cm2, +10µA/cm2]. Additionally, the reference electrode is insensitive to the concrete admixtures which include Na2SO4, NaCl, NaNO3 and NaNO2.Originality/value - The research provides the key element for the corrosion monitoring sensors to integrate structural health monitoring system in future.

Application of fuzzy logic and electrodynamic sensors as flow pattern identifier

Mohd. Fuaad Rahmat, Norhalimatul Saadiah Kamaruddin — 2012-03-23 00:00:00.0

Abstract

Purpose - The use of pneumatic conveying of solid bulk over long distance has become a popular technique due to low operational cost, low maintenance requirement, layout flexibility and ease of automation. In this study, the flow regime in pneumatic conveyor system is identified by electrodynamic sensor placed around the pipe using fuzzy logic tools.Design/methodology/approach - Electrical charge tomography is used to detect the existence of inherent charge on the moving particles through the pipe. Linear back projection algorithm (LBP) and filtered back projection algorithm (FBP) are employed to produce tomography image. Baffles of different shapes are inserted to create various flow regimes such as full flow, three quarter flow, half flow and quarter flow. Fuzzy logic tools are used to identify different flow regimes and produce filtered back concentration profiles for each flow regime.Findings - The results show significant improvement in the pipe flow image resolution and measurement.Originality/value - This paper presents a flow identifier method using electrical charge tomography and fuzzy logic to monitor solid particles flow in pipeline.

Development of Optical Instrument as Turbidimeter: A Comparative Study

Ahmad Fairuz Omar, Mohd Zubir MatJafri — 2012-03-23 00:00:00.0

Abstract

Purpose - This paper presents a comparative study between two low cost turbidimeter designs using a multi purpose Optical Fiber NIR System (OF-NIRS), Optical Fiber NIR System - Modified (OF-NIRS-M) and High Sensitivity NIR System (HS-NIRS) conducted in the development of turbidimeter by closely replicating the existing standard design guideline. Optical method is a typical measuring technique that has been applied intensively for the measurement of water turbidity. Design/methodology/approach - Comprehensive guideline for the development of turbidimeter has been stated by United States Environmental Protection Agency (EPA Method 180.1) and International Organization for Standardization (ISO 7027) and has been used as standards by instrument’s manufacturer world wide including the designs presented in this work. The development commonly does not only establish through physical instrumentation aspects, but also emphasizes on the physics of light-matter interaction such as scattering and absorption that is embedded within the science of turbidity. The individual system design is the assembly of light emitting diode (LED) and photo detector with near infrared (NIR) band, amplifier, 12-bit analogue to digital converter (ADC) and Basic Stamp 2pe microcontroller. Findings - The measurement by OF-NIRS produces coefficient of determination, R2 = 0.8881 with standard error of 20.33NTU while HS-NIRS produces higher precision result with R2 = 0.995 with standard error of 1.809NTU. A modified version of OF-NIRS (OF-NIRS-M) has been introduced and consists of direct emission of NIR radiation to the sample. OF-NIRS-M produces R2 = 0.9921 with standard error of 2.37NTU, a high linearity result, comparable to HS-NIRS. Originality/value - This research introduced a fundamental design of turbidimeter by following closely to existing standard at much lower cost. This work present a comparative study between two main designs that utilize different type of photo detector and amplification circuitry. This work enable related industry to develop their own in house turbidity monitoring system with flexible sensitivity.

Wireless sensing using acoustic signals for measurement of dynamic pressure and temperature in harsh environment

ALFIN LEO, Gino Rinaldi, Ion Stiharu, Rama Bhat — 2012-03-23 00:00:00.0

Abstract

Purpose - It is currently difficult to measure temperature and pressure in harsh environments. Such measurements are limited by either the ability of the sensing element or the associated electrical wiring to withstand the operating environment. This is unfortunate as temperature and pressure are important measurands in various engineering structures as they provide critical information on the operating condition of the structure. Hence, there is a need to address this shortcoming . Such a sensor in place would enhance the operating efficiency thereby reducing the pollution burden and its impact on the environment. Design/methodology/approach - This work describes a co-integrated pressure-temperature wireless sensing scheme. The approach presented herein provides the possibility of measuring dynamic pressure and temperature within an enclosed volume using acoustic signals. Resonance tube physics is exploited for the temperature sensing. A microphone is used to obtain the acoustic signal whose frequency is a function of the temperature and the tube geometry. Findings - The dynamic pressure is measured from the calibrated amplitude of the pressure wave signal measured by the microphone. The temperature can be measured through the shift of the standing wave frequency with a resolution of < 1ºC. The resonance tube can be fabricated using any material that resists harsh environments. The geometry of the tube can be tailored for any specific frequency range, as the application warrants. Also, this provides a means for accurate temperature compensation of pressure sensor data from high temperature environments. A Matlab/Simulink model is developed and presented for the acquisition of acoustic signals through the wall of an enclosed volume. For these applications the standing wave signal transmitted through the enclosure wall becomes a function of the wall material and wall thickness. Preliminary experimental results are presented in which a DC fan is used for generating the dynamic pressure in a varying temperature environment. Research limitations/implications - The major issue is the separation of the noise from the signal. As various applications yield specific signal noise, the problem needs detailed data to be addressed.Practical implications - Temperature and dynamic pressure could be recorded monitored in very harsh environment conditions such as chemical reactors. Originality/value - This work demonstrates the possibility of employing a co-integrated acoustic sensing scheme in which both pressure and temperature are measured simultaneously with a sole sensor. The major advantage with acoustic sensing is the wireless transmission of data. This allows for non-invasive measurement from within enclosed systems. Direct real-time temperature compensation is possible that does not require any compensation circuitry. Hence, pressure and temperature data may be obtained from caustic operating environments whose access is otherwise not feasible.

Local Binary Patterns versus Signal Processing Texture Analysis. A Study from a Performance Evaluation Perspective

Ovidiu Ghita, Dana Elena Ilea, Antonio Fernandez, Paul F Whelan — 2012-03-23 00:00:00.0

Abstract

Purpose - The aim of this paper is to review and provide a detailed performance evaluation of a number of texture descriptors that analyse texture at micro-level such as Local Binary Patterns (LBP) and a number of standard filtering techniques that sample the texture information using either a bank of isotropic filters or Gabor filters. Design/methodology/approach - The experimental tests were conducted on standard databases where the classification results are obtained for single and multiple texture orientations. In our study we have also analysed the performance of standard filtering texture analysis techniques (such as those based of LM and MR8 filter banks) when applied to the classification of texture images contained in standard Outex and Brodatz databases.Findings - The most important finding resulting from this study is that although the LBP/C and the multi-channel Gabor filtering techniques approach texture analysis from a different theoretical perspective, in this paper we have experimentally demonstrated that they share some common properties in regard to the way they sample the macro and micro properties of the texture. Practical implications - Texture is a fundamental property of digital images and the development of robust image descriptors plays a crucial role in the process of image segmentation and scene understanding. Originality/value - This paper contrast from a practical and theoretical standpoint the Local Binary Patterns (LBP) and representative multi-channel texture analysis approaches and a substantial number of experimental results were provided to evaluate their performance when applied to standard texture databases.

Influence of Ta2O5 on Polyaniline surface for Liquid Petroleum Gas Sensing applications

Anil R Koppalkar, Aashis S Roy, Ameena Parveen S S, Ambikaprasad M.V.N prasad — 2012-03-23 00:00:00.0

Abstract

Purpose - LPG sensing at room temperature using conducting polymer polyaniline.Design/methodology/approach - Synthesis of polyaniline and polyaniline Ta2O5 composites in various weight percentages say 10,20,30,40&50%. FTIR,SEM,DC conductivity and sensing property Findings - The 30 wt % composites show maximum sensitivity of 83% to LPG. The selectivity studies revels that, LPG could be sensed better when compared to oxyacetylene and other test gases. Research limitations/implications - Practical implications - Selectivity studies have been carried out.Hence its is to be a better sensor when compared to metal oxides sensors.Originality/value - It is original one.