Mundzir Abdullah

Performance of a New Bundle Fiber Sensor of 1000 RF in Comparison With 16 RF Probe

The comparison of bundle sensor performance between 16 concentric receiving fiber (RF) and 1000 hemicircular RF probes is reported. A theoretical analysis is developed for 1000 RF to support the experimental findings, which uses an electromagnetic Gaussian beam approach to determine the transfer function of the probe. Three linear ranges of the displacement profile can be obtained from each probe, namely, the front slope, the first back slope, and the second back slope. The highest sensitivity obtained by the 16 concentric RF at the front slope range is 5.8148 mV/mm with a resolution . Its lowest sensitivity at the second back slope region is 0.06 mV/mm with an initial resolution of 26 μm. The 16 RF probe produces a better sensor performance both at the front slope and the first back slope region, whereas at the second back slope region, the 1000 RF exhibits a higher sensitivity. Furthermore, a wider linear range is realized through the 1000 RF whereby the front slope and the first back slope are 1.45 and 4.75 mm, respectively. The second back slope of the 16 RF, however, provides a longer linear range 3.0 mm. The latter sensor probe has many potential applications in the longer displacement range, such as position control, micro-displacement sensing in hazardous regions, and automated monitoring control.

In situ measurement of gold nanoparticle production

Abstract. The closeness of the experimental and theoretical values enables the development of an in situ characterization technique to monitor and analyze the production of gold nanoparticles (NPs), overcoming the use of high-end and expensive instrumentation. Gold NPs below the radius size of 10 nm were successfully synthesized in accordance with a few working parameters of pulse laser ablation in a liquid technique. In this report, the size, shape, concentration, and aggregation properties of gold NPs were estimated by the Mie–Gans model based on a reliable and interactive real-time absorption spectroscopy. The major features can be an important means toward determination of efficient process measures, productivity of gold NPs generated, and efficiency of the mass ablation rate. The accuracy in the measurement is confirmed via transmission electron microscopy analysis.

Fiber Optic Displacement Sensor for Industrial Applications

Owing to industrial applications, a fiber optic displacement sensor is introduced to determine the concentration of hydrocarbons in water. Hydrocarbon is organic water pollution. It can harm the environment as well as human being. Thus, a reflective configuration technique was developed to study the hydrocarbon concentrations in the range of 0%-20%. To validate the designed system, two concentrations were selected which represent the lower and higher region. In principle, this sensor is using the concept of intensity modulation as a function of displacement. The optimum displacement between the reflecting target and the fiber optic probe was found to be at 1.5 mm for all concentrations. Furthermore, the peak voltage from each fingerprint was found to be inversely proportional to the tested concentration. This implies that the higher concentration of hydrocarbon tends to detect weaker signal. The sensitivity of the fiber optic displacement sensor was found to be 0.12 mV/wt.% with repeatability of 96%. The resolution of the sensor was 0.027 V, with a limit of detection of 0.23%. The linearity index was found to be 0.98 and 1.04 corresponding to 6% and 14% hydrocarbon concentration, respectively. The simplicity and the credibility of such system offer a good opportunity for industrial applications especially in the environmental sector.

Effect of green laser irradiation on hydrogen production

The effect of green laser irradiation on hydrogen production via water electrolysis was investigated. Diode pumped solid-state laser operating in second harmonic generation was employed as a source of irradiation. The hydrogen production system was also irradiated by a conventional light, a halogen source, for comparison. The best catalyst was identified by mixing distilled water with two types of salt: NaCl and Na2SO4. Optimization of hydrogen production from water electrolysis was realized by using NaCl and green laser irradiation. The power of green laser irradiation and the concentration of NaCl in water contribute to hydrogen production. The hydrogen yield also depends on the distance and direction of the green beam to the electrode.

Fiber optic radial displacement sensor-based a beam-through technique

A fiber optics displacement sensor based on a beam-through technique has wide application due its simplicity, high accuracy, and immune to electromagnetic interference. The fingerprint for such a sensor system is established through the longitudinal displacement. However, it is known that the highest intensity modulation is normally fall at zero distance for the beam-through technique. Thus, it is valuable to take advantage at such optimization position. A novel method is introduced by conducting a fiber optic sensor-based radial displacement. Three types of fiber optic, including 1000, 500, and 265 μm core diameters, were employed to optimize the probe. A Gaussian profile is identified to be the fingerprint for the radial displacement sensor, which entirely different with a linear one for longitudinal displacement. The radial displacement fiber optic sensor is a core diameter-dependent. The bandwidth at full width half maximum tends to be broader with the core diameter of a fiber optic. Higher response of the sensor is achieved at the negative side of the Gaussian curve comparable with positive part. It is realized that the sensitivity of the radial sensor is 7 times higher correspond to core diameter and 3 times better performance than the conventional displacement sensor.

Sugar Detection in Adulterated Honey via Fiber Optic Displacement Sensor for Food Industrial Applications

A fiber optic displacement sensor (FODS) using a transmission technique was developed to detect sugar contents in honey. This was achieved by measuring the output signal of non- and adulterated honey with different addition percentage volumes of sugar (fructose and glucose). Five types of honey samples were adulterated with different percentages of fructose and glucose ranging from 0% to 10%. Blue diode laser at 435 nm was used as a light source in this FODS. The performance of sensor showed that the voltage signal linearly increased with the concentration of adulteration of sugar. In contrast, the refractive index of the adulterated honey is found decreasing with the concentration of sugar. This means the higher sugar contents in adulterated honey the lower is the refractive index leading to high transmission in FODS. Thus, FODS based on a transmission technique has a potential to detect the sugar content in adulterated honey. The simplicity, faster, and cost effective made FODS as a promising technique for food industry.

Stimulated emission cross section at various temperatures based on laser performance

The determination of stimulated emission cross sections at various temperatures is reported. Neodymium doped yttrium orthovanadate crystal (Nd:YVO4) was employed as a gain medium. The temperature of the crystal holder varied between 20 and 60 °C. The cross section was determined based on laser performance. The slope efficiency of the diode end-pumped Nd:YVO4 laser system decreased from 40.2% to 31.7%, while the threshold power increased from 0.744 to 1.028 W. The far-field beam diameter increased linearly with the absorbed pump power at a constant temperature. There was no correlation between the rate of change of the beam diameter with temperature due to mechanical stress fluctuation. The stimulated emission cross section was found to decrease at a rate of −0.45% °C−1, which concurs with previous works. The stimulated emission cross section of various solid-state gain mediums can be determined through this method.

Determination of Hydrocarbon Level in Distilled Water via Fiber Optic Displacement Sensor

Fiber optic displacement sensor offers a feasible way to detect hydrocarbon level in water. A reflective light intensity modulation technique is accomplished to detect hydrocarbon concentration in the ranges of 0%-20%. The reflective configuration technique enables the sensor to collect output voltage at a different displacement. The output voltage decreases linearly with hydrocarbon level at a corresponding optimized displacement of 1.5 mm. Linearity index close to one indicates that a high confident degree the sensor. Simple in design and low cost, makes this system as a promising sensor for determination of hydrocarbon level in water.

Optimization of the super lateral energy in laser surface alloying of aluminum

An aluminum substrate has been alloyed with an iron and copper mixture by a laser induced plasma technique. The nanosecond pulse duration and the high plasma temperature expose the interacting materials to decalescent and recalescent regions, contributing to the formation of new chemical composites such as AlFeCu, AlFe, AlCu and CuFe. The microstructure of the alloyed surface is observed to be heterogeneous, with no crack formation and with few pores. The hardness of the laser treated surface is 103?HV, seven times harder than that of the substrate (15?HV) at a corresponding super lateral energy of 5282?mJ?cm?2.