Kheamrutai Thamaphat

Characterization of Apatite from Human Teeth via XRD, FT-IR and TGA Techniques

Human teeth (HT) are natural composites which consist of nanohydroxyapatite (HAp) arranged in lamellae and bound to collagen. In present study, prepared HT powders with different ages were characterized by X-Ray Diffraction (XRD), Fourier transform infrared (FT-IR) and thermogravimetric anlysis (TGA) techniques. HT at age ranges of 1-10, 11-20, 21-30, 31-40, 41-50 and 51-60 years old were selected for tests. To prepare samples, human teeth were washed in boiling water for 1 h and left in 1 M KOH solution for 6 h to remove any organic material. After HT samples were cleaned with ultrasonic in ethanol, they were then finely grounded using agate mortar. The results from XRD indicate that the major diffraction peaks of all samples with different ages were very closely identified to that of stoichiometric HAp. All HT powders were found to be nanocrystalline structure. Furthermore, it was found that the decrease in HAp crystallinity seem to increase with higher age of 31-40 years old. To investigate chemical structure confirmed by FT-IR, All HT powders showed the band positions and function groups, which are similar to that of HAp. group found in chemical structure indicates the structure of carbonated apatite. TGA results were found that the increase of weight loss seem to increase with higher age.

ESR Spectrometer as a Possible Tool for Rapid Analysis of Cane Sugar Purity

A method for quantitative/qualitative determination of cane sugar purity by ESR is devised. Refined sugar, plantation white sugar, soft brown sugar and raw sugar are used as samples in this work. The sucrose radical is produced by pulverization of sugar and it increases as the particle size decreases. Based on pulverization-induced sucrose radical, ESR study demonstrates the effects of sugar purity on characteristic of ESR spectrum. The relationship between the sucrose contents and peak area under the ESR spectrum is manifested. It is found that the peak area or sucrose radical concentration increases linearly with the increase of sucrose content. Using the linear regression method, the sucrose amount can be revealed. This approach is a promising fast and accurate method for sugar purity analysis.

Rapid screening for anthocyanins in cane sugars using ESR spectroscopy

Anthocyanin, which is soluble in water and released into sugar steam during extraction, was investigated in this study. The anthocyanin content in refined sugar, plantation white sugar, soft brown sugar and raw sugar was determined using electron spin resonance (ESR) spectroscopy, which was operated at room temperature, and compared with spectra from standard anthocyanin. The ESR spectra of red and violet anthocyanins was predominantly g ≈ 2.0055, which corresponded to an unpaired electron located in the pyrylium ring. Signals for Fe(III) and Mn(II), which naturally occur in plants, were found in raw sugar, soft brown sugar and standard anthocyanin but were absent from refined sugar and plantation white sugar due to the refining process. In addition, the ESR results were correlated with the apparent colour of the sugar, which was determined using the method of the International Commission for Uniform Methods of Sugar Analysis and inductively coupled plasma optical emission spectroscopy.

Synthesis and Characterization of Pure Natural Hydroxyapatite from Fish Bones Bio-Waste

The objective of the present study was the qualitative comparison of hydroxyapatite (HAP) extracted from bio waste by different methods. Fish bones obtained from mango fish (Oreochromis niloticus) were used as natural source for HAP synthesis. Three different processes were applied to extract the natural HAP: annealing at 400-1000 °C (F400-F1000), H2O2 cleaning and NaOH cleaning. A combination of TGA/DSC analyses, XRD spectrometry, FTIR spectroscopy and scanning electron microscopy were utilized for characterization. They indicated that all methods have the ability to eliminate the organic compounds present in the fish bones. However, annealing of the bone sample was found to be more efficient approach in reducing the amount of organic phase; only inorganic phase was remained in F600, F800 and F1000. For the HAP crystallinity, treatment with H2O2, NaOH, and heating up to 400 °C did not create notable changes of HAP original crystallinity. On the contrary, HAP crystallinity was increased slowly from 400 to 600 °C, outstandingly from 600 to 800 °C and remained almost constant from 800 to 1000 °C.

Revelation of Causes of Colour Change in Beryllium-Treated Sapphires

Blue sapphires are treated with Be in oxidizing atmosphere to change the blue colour into yellow. Untreated and Be-treated samples are examined using laser ablation inductively coupled-plasma-mass spectrometry (LA-ICP-MS), electron spin resonance (ESR) and ultraviolet–visible (UV–vis) spectroscopy. The results show that the yellow colouration in Be-heated blue sapphires is not due to Be diffusion from the surface of sapphire. Be behaves as a sole catalyst in this process. We find that the charge transfer between the ferrous (Fe2+) and ferric (Fe3+) is the reason of the colour change. The above conclusions are confirmed by ESR measurements to determine the connections between the Fe3+ ions before and after Be-treated heat treatments.

Removal of Cu2+ from Aqueous Solutions by Magnetic Nanoparticles-Pomelo Peel Composite

Many researchers have currently interested in using Fe3O4 magnetic nanoparticles (MNPs) impregnated onto agricultural wastes for removal of heavy metal ions in wastewater treatment process. In this work, the MNPs-pomelo peel powder (MNPs-PP) composites were developed and their adsorption capacities of heavy metal ions were studied as well. The MNPs-PP samples were synthesized by co-precipitation method in different ratios; 2:1, 2:2, 2:4, 2:5, and 2:6 (by weight). The results showed that the as-synthesized MNPs were mainly spherical shape with an average particle size of approximately 12.7 ± 0.6 nm. Then, the MNPs, PP and MNPs-PP in different ratios were used as adsorbents for adsorption of 25 ppm Cu2+ in aqueous solution. The pH and temperature of solution were kept constant at 5 and 30 °C, respectively. From the experiment, it was found that the adsorption capacities decreased in the following order: PP > MNPs-PP (2:6) > MNPs-PP (2:5) > MNPs-PP (2:4) > MNPs-PP (2:2) > MNPs-PP (2:1) > MNPs. It indicated that the adsorption capacity of as-synthesized MNPs-PP is significantly higher than that of sole MNPs. Furthermore, the adsorption capacities of MNPs-PP increased with increasing the weight ratio of PP. The MNPs-PP developed herein has demonstrated not only high adsorption efficiency but also have shown additional benefits such as ease to synthesis, cost-effectiveness, environmental-friendliness, and ease to separate from treated water by an external magnet.

ELECTRON SPIN RESONANCE INVESTIGATION OF FREE RADICALS PRODUCED IN PULVERIZED NON-IRRADIATED SUGAR

An electron spin resonance (ESR) study of the effects of pulverization on non-irradiated crystalline sugar was performed. It indicated that the crystalline sugar before being ground did not give any ESR signal but an ESR signal was found in pulverized sugar. These results implied that free radicals were produced by pulverization. Moreover, the free radical density increased as the particle size decreased. From high-performance liquid chromatography analysis and the ESR spectrum of non-irradiated powdered sucrose, it can be inferred that the pulverization-induced free radical in sugar is a sucrose radical. Recently, many researchers have reported that sugar irradiated with 60Co γ-rays at different doses produced stable sucrose radicals. This may imply that the process of sucrose radical formation by mechanical stress is similar to that for irradiation.

Development of Experimental Set for Determination of Refractive Index of Liquid Using Optical Fiber

The construction of an experimental set for measurement of refractive index of liquids using fiber optics has been described in this work. The experimental set is aimed for demonstration in physics high school class. A prototype fabricated in laboratory composes of plastic-clad-plastic (PCP) optical fiber with the length of 50 cm, fiber optic transmitter diode, fiber optic phototransistor detector, and liquid container. The diameter and refractive index of the core of PCP optical fiber were 1 mm and 1.492, respectively. The thickness and refractive index of fiber cladding were 1.2 mm and 1.417, respectively. The fiber cladding surface at the central region was removed approximately 5 cm long to form a sensor area. This sensor area was inserted into a cylindrical glass which acted as the container. One end of the fiber was connected to the transmitter diode with a wavelength of 660 nm, and the other end was connected to the detector. A digital multimeter was used to measure an output voltage from the detector. In this work, the effect of water temperature on its refractive index was determined. The results showed that the water refractive index decreased with increasing water temperature and result in the increase of measured output voltage. Furthermore, it was found that the output voltage measured at different temperatures of water depends linearly on water refractive index.

Durian Peeling Extract Mediated Green Synthesis of Silver Nanoparticles

In this work, silver nanoparticles (AgNPs) were successfully synthesized from AgNO3 through a simple and eco-friendly method, also called the green synthesis, using Mon Thong durian (Durio zibethinus L.) peeling extract. The main role in synthesis mechanism of AgNPs is using polysaccharides in durian rind as a reducing agent as well as stabilizer. The appearance of a yellowish-brown color in mixture of AgNO3 solution and durian rind extract is the indication of formation of AgNPs. The synthesized AgNPs were characterized by UV-visible spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD) spectrometry. The AgNPs were found to be polycrystalline in nature and spherical particles with diameter of 11.7 ± 3.2 nm. The crystallinity with fcc phase is evidenced by clear lattice fringes in SAED pattern and diffraction peaks in the XRD pattern corresponding to the (111), (200), (220), and (311) planes.

Uncomplicated Setting Apparatus for Measurement of Fluid Flow Rate Using Laser Doppler Technique: Physics Teaching

Laser Doppler velocimetry (LDV) or laser Doppler anemometry (LDA) is the technique of using the Doppler shift in a laser beam to determine the fluid velocity. In this work, dual beam mode (two incident beams, single observation location) was selected to use. A cost effective and easy module for measurement of water flow rate was designed and constructed. A He-Ne laser with a wavelength of 632.8 nm was used as a light source. The laser was passed through a beam splitter and divided into two beams with identical intensity and coherence. Subsequently, the two laser beams travelled to a focusing lens with a focal length of 100 mm and focused on a center of water flow channel in quartz cuvette with a dimension of 1 × 1 × 5 cm3. The beam angle was set at 4.96°. When the seeding particles, bubbles and microorganism in water, were moving through the intersection point of two beams, the light was scattered. The scattered light was collected by photodetector connected to processing system. The frequency of scatterred light is shifted according to the Doppler shift relations due to effect of Rayleigh scattering. The water flow rate can be calculated from Doppler shift frequency.