Journal of Magnetism and Magnetic Materials. Volumes 198-199, 1 June 1999,

Improving the tribological characteristics of piston ring assembly in automotive engines using Al2O3 and TiO2 nanomaterials as nano-lubricant additives

The Williamson-Hall (W-H) equation, which has been used to obtain relative crystallite sizes and strains between samples since 1962, is revisited. A modified W-H equation is derived which takes into account the Scherrer equation, first published in 1918, (which traditionally gives more absolute crystallite size prediction) and strain prediction from Raman spectra. It is found that W-H crystallite sizes are on average 2.11 ± 0.01 times smaller than the sizes from Scherrer equation. Furthermore the strain from the W-H plots when compared to strain obtained from Raman spectral red-shifts yield factors whose values depend on the phases in the materials – whether anatase, rutile or brookite. Two main phases are identified in the annealing temperatures (350 °C–700 °C) chosen herein – anatase and brookite. A transition temperature of 550 °C has been found for nano-TiO2 to irreversibly transform from brookite to anatase by plotting the Raman peak shifts against the annealing temperatures. The W-H underestimation on the strain in the brookite phase gives W-H/Raman factor of 3.10 ± 0.05 whereas for the anatase phase, one gets 2.46 ± 0.03. The new βtot2cos2θ-sinθ plot and when fitted with a polynomial yield less strain but much better matching with experimental TEM crystallite sizes and the agglomerates than both the traditional Williamson-Hall and the Scherrer methods. There is greater improvement in the model when linearized – that is the βtotcos2θ-sinθ plot rather than the βtot2cos2θ-sinθ plot.

Strain and grain size of TiO2 nanoparticles from TEM, Raman spectroscopy and XRD: The revisiting of the Williamson-Hall plot method

TiO2 photocatalyst hybridized with new multilamellar vesicles (MLVs) mesoporous ZSM-5 substrate (TiO2/ZSM-5) were prepared by the direct templating technique for decolorization and minerlization of methyl orange (MO) dye effluent. The synthesized materials were characterized by X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), Fourier-transformed infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET). It was found that the specific surface area (SBET) of the synthesized TiO2/ZSM-5 was 1151 m2 g−1. The results also indicated that the zeolite structure conserves mesoporous structure after the removal of surfactant templates. Several parameters were also investigated such as the effect of catalyst types, pH, adsorption/photocatalysis phenomenon and contact time. Under 180 min solar irradiation, MO dye was efficiently decolorized and mineralized to be 99.55% and 99%, respectively, at an initial MO concentration of 20 mg L−1. Furthermore, the photocatalysis kinetic fit the pseudo-second-order model well and a great potential for saving energy associated with its recyclability. Therefore, the synthesized TiO2/ZSM-5 could be used as a promosing photocatalysis for fast removal and treatment of coloured wastewater.

Synthesis a novel multilamellar mesoporous TiO2/ZSM-5 for photo-catalytic degradation of methyl orange dye in aqueous media

The present overview is intended to point the readers' attention to the important subject of calcium orthophosphates (CaPO4). This type of materials is of the special significance for the human beings because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with CaPO4, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenorthophosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of CaPO4. Similarly, dental caries and osteoporosis might be considered as in vivo dissolution of CaPO4. In addition, natural CaPO4 are the major source of phosphorus, which is used to produce agricultural fertilizers, detergents and various phosphorus-containing chemicals. Thus, there is a great significance of CaPO4 for the humankind and, in this paper, an overview on the current knowledge on this subject is provided.

/pdf/calcium-orthophosphates-capo4-occurrence-and-properties-a4heufqdoi.pdf

Calcium orthophosphates (CaPO4): occurrence and properties

In this study, the commercial TiO2 nanopowder and micropowder of anatase phase and rutile phase have been characterized by x-ray diffraction (XRD) and transmission electron microscopy (TEM). XRD patterns of nano-TiO2 in rutile and anatase phases exhibit broad peaks whereas both phases of micro-TiO2 demonstrate very sharp peaks. TEM images show that the grain size of TiO2 micropowders and TiO2 nanopowders are 0.3-0.7 ∝m and 10 nm, respectively. The selected-area electron diffraction patterns of TiO2 nanopowders in rutile and anatase phases are consistent with XRD results.

Phase Characterization of TiO2 Powder by XRD and TEM

Photo-irradiation induced green synthesis of highly stable silver nanoparticles using durian rind biomass: effects of light intensity, exposure time and pH on silver nanoparticles formation

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.

http://iopscience.iop.org/article/10.1088/0256-307X/25/6/015/pdf

Revelation of Causes of Colour Change in Beryllium-Treated Sapphires

Urinary tract infections, especially catheter-associated urinary tract infections (CAUTIs), are the most common type of nosocomial infections. Patients with chronic indwelling urinary catheters have a higher risk of infection due to biofilm formation on the urinary catheter surface. Therefore, in this work, a novel, cost-effective antimicrobial urinary catheter was developed using green technology. Silver nanoparticles (AgNPs) synthesized from Mon Thong durian rind waste were used as an antimicrobial agent for the prevention of infection. Flavonoids, phenolic compounds, and glucose extracted from durian rind were used as a reducing agent to reduce the Ag+ dissolved in AgNO3 solution to form non-aggregated AgNPs under light irradiation. The AgNPs were simultaneously synthesized and coated on the inner and outer surfaces of silicone indwelling urinary catheters using the dip coating method. The results showed that the antimicrobial urinary catheter fabricated using a 0.3 mM AgNO3 concentration and 48 h coating time gave the highest antibacterial activity. The as-prepared spherical AgNPs with an average diameter of 9.1 ± 0.4 nm formed on catheter surfaces in a monolayer approximately 1.3 µm thick corresponding to a 0.712 mg/cm2 silver content. The AgNP layer was found to damage and almost completely inhibit the growth of Escherichia coli cells with antibacterial activity by 91%, equivalent to the commercial, high-price antimicrobial urinary catheter. The cumulative amount of silver released from the coated catheter through artificial urine over 10 days was about 0.040 µg/mL, which is less than the silver content that causes tissue and organ toxicity at 44 µg/mL. Thus, we concluded that the developed antimicrobial urinary catheter was useful in reducing the risk of infectious complications in patients with indwelling catheters.

https://www.mdpi.com/2227-9717/8/12/1630/pdf

Kheamrutai Thamaphat

Papers

Phase Characterization of TiO2 Powder by XRD and TEM

Photo-irradiation induced green synthesis of highly stable silver nanoparticles using durian rind biomass: effects of light intensity, exposure time and pH on silver nanoparticles formation

Revelation of Causes of Colour Change in Beryllium-Treated Sapphires

In Situ Deposition of Green Silver Nanoparticles on Urinary Catheters under Photo-Irradiation for Antibacterial Properties

A force measurement method using the optical fibre beam