Water level measurement via polymer-fiber Bragg grating sensor

In this paper, a new design of sensor head to monitor water level inside the tank based on fiber Bragg grating (FBG) was demonstrated. The sensor head consisted of an FBG placed under a very thin polymer plastic sheet layer. This sensor head acts as a sensitive diaphragm to sense water level based on hydrostatic pressure caused by the liquid weight. The hydrostatic pressure imposed on the sensor head produced strain in the embedded FBG, which caused a shift in Bragg wavelength detected by the optical spectrum analyzer. A calibration curve to relate liquid level and shift in the Bragg wavelength was constructed. A linear relationship between the shift in Bragg wavelength and the water level up to 70 cm height with a sensitivity of 2 pm/cm is achieved in this work

Comparison of water level measurement performance for two different types of diaphragm using fiber bragg grating based optical sensors

A sensor head incorporating a diaphragm was designed and fabricated for water level measurement. It operates in the range of 0-70 cm column height, equivalent to a pressure in atmospheric pressure of 0-6. 86 kPa. The fiber Bragg grating (FBG) was attached on the two types of diaphragm to detect the change in the hydrostatic pressure caused by water at different levels. The diaphragms performance by comparing the sensitivity in within the mentioned range. Optical spectrum analyzer (OSA) was used to record the shift in the Bragg wavelength λB at different water level. The sensitivity of water level measurement using a silicone rubber diaphragm found to be 9.81 pm/cm for 70 cm in water level, while the sensitivity for polymer plastic diaphragm found to be 2 pm/cm at the same leve

Laser-induced breakdown spectroscopy (LIBS) for printing ink analysis coupled with principle component analysis (PCA)

Laser-induced breakdown spectroscopy (LIBS) has been applied to perform elemental analysis of printing ink samples. Samples of black printing inks from three types of printers viz. inkjet, laser-jet, and photocopier (three different brands for each type) and one control sample (blank white A4 paper) were analysed under optimised conditions. Results revealed that the LIBS method when coupled with PCA was able to provide discriminative evidence on elemental differences among all the different printing inks. Considering its time and cost effectiveness as well as requiring only minute amount of sample with no sample pre-treatment steps, the combination of LIBS and PCA may prove useful for forensic questioned document practical caseworks

Volatolomics combined terahertz time - domain spectral analyses of colon cancer in vitro

Terahertz time-domain spectroscopy (THz-TDS) offers a great advantage for the analysis of biological samples. In this study, we combined THz-TDS with volatolomics analysis and analyzed 2 colon cell lines via in vitro settings. The release of volatile organic compounds (VOCs) was measured from the normal colon (CCD112CoN) and cancer colon (COLO320DM) cell lines which were grown in sealed flasks. Data validation were carried out with principal component analysis (PCA) and partial least square (PLS) scores while the chemometric analyses were performed using Camo Unscrambler X software. In-depth THz-TDS spectral analysis of the cancer colon (COLO320DM) cell line shows significant traces of benzamide gas when validated using gas chromatography-mass selective detection (GC-MSD) system. This preliminary data shows the potential use of identification and quantification of benzamide compound in the cancer colon cells and this could provide useful insight towards cancer drug design and therapy

Steel wire cleaning using cold plasma

Current galvanizing process used hydrochloric acid to remove oxide layer and mild acidic bath to remove oil on metal wire surface. These cleaning processes are compulsory before steel wire coated with zinc. These chemicals cleaning technique cause ecological harm and produce toxic waste. To consider of minimizing these problems, cold plasma was introduced for metal wire cleaning. Previous research already proves that cold plasma capable to remove oil by using dielectric barrier discharge (DBD) and remove oxide layer on copper by using RF plasma discharge. Therefore, in this research, the same plasma discharge system that is DBD was used to remove oil and oxide layer on steel wire. 8kV of voltage and air was used to generate plasma. By using copper and steel wire as electrode, it can remove oil around 82% and oxide layer around 54%

Investigation of Michelson interferometer fiber temperature sensor based on single mode-multimode-single mode fiber structure

A simple fiber temperature sensor based on Michelson interferometer is investigated experimentally. The sensor is formed successive splicing of a single mode fiber (SMF) spliced to a short section of multimode fiber (MMF) followed by another SMF, which also known as single mode-multimode-single mode (SMS) structure. Temperature response of three different sensor lengths of 10 mm, 20 mm and 30 mm are experimented with increasing and decreasing temperature. The sensor exhibits good linearity, stability and repeatability for the test range from room temperature to 180 °C. The highest sensitivity is attained by the 10 mm sensor with response ~0.108 nm/°C. Factors that affect sensitivity are discussed and related issues are addressed. This sensor is most suitable for low to intermediate temperature applications

Spawn treatment by cold plasma for increase mushroom germination and production

Cold plasma technology has found favour in the agricultural industry for growth stimulating by environmental friendly approach. However, there are still leaking studying of cold plasma technology on the mushroom needs. Current convectional mushrooms germination process requires long duration (∼6 weeks) for fruiting to growth. Therefore, this study aims to investigate the cold plasma efficacy towards the oyster mushroom germination speed and fruiting body production. By using novel atmospheric cold plasma pen system, the mushroom spawn grains were generates towards the spawn. Atmospheric pressure with flow rate of 4, 5 and 6 SLM by considering different duration plasma exposure (0, 5, 15, 30, 45 and 60 seconds) with ∼7 kV of supply voltage was supplied. The efficiency of the treatment was characterised by mushroom cultivation performance particularly on (i) mycelium growth rate and (ii) mushroom fruiting body productions. The results show cold plasma processing parameter, flow rate and treatment time absolutely influence the mushroom germination and production. CP pen system optimized at 5 SLM and 15 s presents triple production of mushroom weight and speed the mycelium growth rate (only 4 weeks) compared to control spawn grains (6 weeks). As conclusion, cold plasma pen system capability applies in mushroom industry

Controlled pore diameter in porous anodic aluminium oxide templates for nanotube/nanowire fabrication

A porous anodic aluminium oxide (AAO) templates were fabricated on aluminium by electrodeposition method using a two-step anodization process. The AAO templates were anodized in 0.3 M oxalic acid solution by applying a constant voltage of 40V, which was afterward treated with chemical etching process in a mixed solution of 6% phosphoric acid and 1.8% chromic acid, respectively. The temperature was kept constant in 15oC during the anodization process and the anodization time were done between 20 to 60 min. All the samples were characterized using by scanning electron microscopy (SEM) to study the surface morphology of AAO templates. It was found that the pore diameters of AAO templates can be controlled by changing the anodizing time. The influence of the electropolishing were also discussed. Highly uniform self-ordered AAO template were effectively formed from these polished foils via an anodizing process

Novel study of design for miniature correlation spectroscopy handheld gas sensor for methane (CH₄) using 2.3 µm wavelength band

A highly selective methane gas sensor, using the correlation spectroscopy technique, has been constructed. This sensor is handheld and has a compact folded cell arrangement; it operates with 2.3 µm switched LED sources. The selected methane absorption band at 2.3 µm is relatively strong, even over a short path length (10 cm), yet this wavelength still allows the use of commercial glass lenses and optical windows, a simple 45° silicon wafer slice as a beam splitter and low noise InGaAs detectors. A noise-limited detection sensitivity of 0.21% by volume with a measurement time constant of 0.1 s was achieved