Figure 1 - uploaded by Ahmad Fairuz Omar
Content may be subject to copyright.
Source publication
![The Technical Specifications of blue and red LED [5]](profile/Ahmad-Omar-5/publication/241537500/figure/tbl1/AS:822878673059842@1573200972708/The-Technical-Specifications-of-blue-and-red-LED-5_Q320.jpg)
The development of water quality
fiber sensor through spectroscopy
analysis utilizes the emission of incident light and detection of backscattered light through fiber optic cables as key elements of the design. The system has the capability to detect the light scattered 180° away from the incident light when there is an interaction between the li...
Context in source publication
Citations
... They used the blue and red light to determine the turbidity concentration owing to the step size of 10 mg/L in the water. They demonstrated that blue light (R 2 ∼ 0.958) is a better sensing response than red light (R 2 ∼ 0.867) comprising good sensitivity and excellent reliability [40]. ...
The importance of nanocomposite-based fiber optic sensors has immensely increased in the fields of chemical, gas, bio-analytes, food processing, environmental indoor/outdoor air quality monitoring, safety issues, and heavy metal for accurate detection due to advancements in modern science and technology. Exposure to harmful analytes that exceed the optimum concentrations is dangerous and it is essential to monitor and keep human beings healthy. The growing prevalence of the health risks associated with various toxic/polluting gases, chemicals, and heavy metals, as well as the need for rectification measures, the standard regulations have prompted extensive research into the development of efficient optical sensors that can detect trace levels of pollution from various sources. For sensing various harmful gases, chemicals, and heavy metals, nano thin film optical sensor structures based on various sensing materials such as metal oxide semiconductors, polymers, metals, carbon nanotubes, graphene, and others have been explored. These sensors are found to have a better sensing response in terms of sensitivity, selectivity, response time, recovery time, and repeatability than uncoated-based optical sensors. Various optical sensing setups to detect gases (NH
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub>
, NO
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>
, CO, CO
<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>
) and heavy metal substances
$\vphantom {^{\int ^{A}}}$
such as (Hg
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+2</sup>
, Cr
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+2</sup>
, Cu
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+2</sup>
, Pb
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+2</sup>
, Cd
<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+2</sup>
) are frequently detected harmful compounds in the environment in the present report for the different sensing methods. We focused on the recent advancement of the nanomaterial-based fiber optic sensor for gas, chemical, and heavy metal detection for monitoring environmental health in the review article.
... The monitoring of turbidity is necessary for different purposes, sustaining the aquatic ecosystem [5,6] and domestic water quality system [7]. Several studies have been demonstrated to detect various physical changes of polluted water using fiber optic sensors [8][9][10][11][12]. Common online instruments that offers in-situ monitoring are applied in most turbidity sensors for measurement in streams, rivers, lakes and oceans [2]. ...
... In this application, plastic optical fiber (POF) has the advantage of high transmission in the visible-near infrared (VIS-NIR) range, high mechanical stability and resistance to chemical degradation. Hands on and simple designs without involving high budget equipment were attempted by mechanically polishing the fiber to make bundle sensors [2,3,[8][9][10][11][13][14][15][16][17]. Theoretical studies on wave propagation of side by side fibers based on evanescence have been reported in journals and literature [14][15][16][17][18]. Utzinger and Richards-Kortum showed that the incident angle on the exit surface of fiber reaches the critical angle, c the light is total internally reflected and leave through the side wall of the emitting fiber [11]. ...
The construction and working principles of a plastic fiber sensor for examining the level of turbidity is studied in this paper. This work focuses on designing an inexpensive turbidity sensor that incorporates a pair of multimode fibers (MMF) that are attached side by side and their beveled tips are mounted vertically. The efficiency of different beveled angles is evaluated by simulation with Tracepro software. The reflected signal is collected by immersing the sensor head into a water mixture and analyzed for various concentration. It was found that there is a linear increment of output intensity when concentration of mixture is increased. The turbidity sensor is tested with real samples that are collected from lake, river and coastal areas to demonstrate its consistency with commercial apparatus in natural compounds. The results showed that the proposed sensor structure is able to produce reliable results in a dynamic range of detection from 0 to 1000 Nephelometric Turbidity Unit (NTU) to facilitate practical field measurements.
... However, they did not include the test results related to using those probes to identify the performance and efficiency of these sensors in WQM. Omar and MatJafri (2007) developed a sensor with a light backscattering technique. Subsequently, they developed another fiber-optic probe using transmittance and 90 • light-scattering technique (Omar and Mat-Jafri, 2008). ...
Online drinking water quality monitoring technologies have made significant progress for source water surveillance and water treatment plant operation. The use of these technologies in the distribution system has not been favorable due to the high costs associated with installation, maintenance, and calibration of a large distributed array of monitoring sensors. This has led to a search for newer technologies that can be economically deployed on a large scale. This paper includes a brief description of important parameters for drinking water and current available technologies used in the field. The paper also provides a thorough review of the advances in sensor technology for measurement of common water quality parameters (pH, turbidity, free chlorine, dissolved oxygen, and conductivity) in drinking water distribution systems.
... Due to the very small size of fiber diameter, the coupling between fiber cables to the detector is very crucial. Therefore, a highly sensitive detector is required so that the small resolution of turbidity can be registered by the system [51]. The application of fiber optic cables will introduce a flexible interface between the spectroscopic sensory system and the sample to be examined in-situ [52]. ...
... However, since it has the highest attenuation, plastic fiber is most suitable to be used for short distances [53]. The optical fiber sensor for water quality measurement developed by Omar and MatJafri [51] consist of two emitter and detector systems that are specifically designed to measure water turbidity level in mg/L units. However, the system can be recalibrated for the measurement in NTU units, which are the standard units for turbidity. ...
... d a higher intensity of LED and a better sensitivity of detector. The detection of scattered light was then submitted to Basic Stamp 2 (BS2) microcontroller for data interpretation and display.Figure 7 shows the detector circuit design with the output pin (voltage) from the photo detector that is connected to the input of the amplification circuit. [51]. The conceptual design of the overall system is illustrated inFigure 8. For every turbid water sample, the TSS (total suspended solids) capacity in the water will be represented by the amount of light received by the detector. The result will be represented in the unit of RCTIME. RCTIME is the discharging time of the capacitor (C1) conn ...
Turbidimeters operate based on the optical phenomena that occur when incident light through water body is scattered by the existence of foreign particles which are suspended within it. This review paper elaborates on the standards and factors that may influence the measurement of turbidity. The discussion also focuses on the optical fiber sensor technologies that have been applied within the lab and field environment and have been implemented in the measurement of water turbidity and concentration of particles. This paper also discusses and compares results from three different turbidimeter designs that use various optical components. Mohd Zubir and Bashah and Daraigan have introduced a design which has simple configurations. Omar and MatJafri, on the other hand, have established a new turbidimeter design that makes use of optical fiber cable as the light transferring medium. The application of fiber optic cable to the turbidimeter will present a flexible measurement technique, allowing measurements to be made online. Scattered light measurement through optical fiber cable requires a highly sensitive detector to interpret the scattered light signal. This has made the optical fiber system have higher sensitivity in measuring turbidity compared to the other two simple turbidimeters presented in this paper. Fiber optic sensors provide the potential for increased sensitivity over large concentration ranges. However, many challenges must be examined to develop sensors that can collect reliable turbidity measurements in situ.
... The design of fiber optic probe in the measurement of the backscattered light is very important in the spectroscopy application. The measurement of the backscattered light is always crucial since its intensity is very low and will require a very high sensitivity optical sensor to interpret the signal (2). Due to that, proper fiber probes configurations may assist in reducing this problem. ...
... This phenomenon is called as diffuse reflectance or scattered light. However, if the light path diverged through a predicted angle and unscattered, it is called as specular reflection which obey the law of reflection (2). ...
This research introduced the simulation and the analysis performed through experimental setup to identify the best reflectance fiber probe configuration that able to measure the highest intensity of reflectance light from a sample. The reflectance fiber probe consists of two strands of fiber cable, one is for light emitting and another is to retrieve the reflected (or backscattered light) from the sample. The result in this research will assist in the entire development of spectroscopy kits for biological applications. The high intensity of backscattered light is desired in the measurement since it should meet the capability of the optical sensor to perform its measurement with high efficiency and accuracy. The fiber probe used in the design has the core with diameter of 1mm. The simulation of the optical design was conducted using ASAP software. It is identified that the highest intensity of backscattered light can be measured when the distance between probe’s end and the 100% reflective sample is put at 2 mm and the distance between the emitting and retrieving fiber cable is set to be at 0 mm. The consecutive simulation shows that the further the distance between the two fiber cables will lead to decreasing capacity of backscattered light.
A real-time turbidimeter based on time-correlated single photon counting (TCSPC) was developed to measure the low-level turbidity for drinking water. To improve measurement accuracy, we use a single-photon avalanche diode (SPAD) with high sensitivity to accurately detect the intensity of weak scattering light. A novel statistics principle-based TCSPC technique was applied in this system to reduce the fluctuation of measurement and improve the stability of turbidity measurement. Thanks to the SPAD with short response time and the digital output of single-photon detecting module, the real-time and steady measurement of low turbidity is finally implemented. Experimental tests for the turbidimeter’s performance were described and the results showed that 0.1 Nephelometric Turbidity Units (NTU) can be measured stably in the range of 0-400 NTU within 1 s. On the basis of the theoretical analysis, a turbidity measurement model was proposed. It was found that a tradeoff between the high measurement resolution and wide linearity range should be considered adequately depending on the practical applications. By adjusting the system parameters, we demonstrated that the linear range of measurement could be expanded in the regime of low turbidity, while maintaining high resolution of this system. The proposed turbidimeter has advantages of high resolution, wide linear range, and short response time, which is sufficient for many applications, including the real-time online turbidity or particle concentration monitoring.
This research is the continuance of the previous developed water quality fiber sensor by Omar et al (2007). The application of spectroscopy analysis is the major tasks established in the measurement of the capacity of total suspended solids (TSS) in water sample in the unit of mg/L. The interaction between the incident light and the turbid water sample will leads the light to be either transmitted through the water sample or absorbed and scattered by water molecules and TSS particles. The resultant light produced after the interaction will be collected by plastic optical fiber located at 180deg (transmittance measurement technique) and 90deg (90deg scattering measurement technique) from the incident light. The measurement is done through BLUE and RED Systems with peak response of emitter and detector at 470 nm and 635 nm respectively. Signal interpretation and data display is established through Basic Stamp 2 microcontroller. Transmittance measurement technique has a capability to sense the amount of solids suspended in water as low as 20 mg/L. 90deg measurement technique has a capability to sense the amount of solids suspended in water as low as 10 mg/L. Both measurement techniques recorded a very good linear correlation coefficient and low standard error.
