Analysis of White Latex Paints using Laser Induced Breakdown Spectroscopy for Forensic Applications

The analysis of white latex paint is a problem for forensic laboratories because of difficulty in differentiation between samples. Current methods provide limited information that is not suitable for discrimination. Elemental analysis of white latex paints has resulted in 99% discriminating power when using LA-ICP-MS; however, mass spectrometers can be prohibitively expensive and require a skilled operator. A quick, inexpensive, effective method is needed for the differentiation of white latex paints. In this study, LIBS is used to analyze 24 white latex paint samples. LIBS is fast, easy to operate, and has a low cost. Results show that 98.1% of variation can be accounted for via principle component analysis, while Tukey pairwise comparisons differentiated 95.6% with potassium as the elemental ratio, showing that the discrimination capabilities of LIBS are comparable to those of LA-ICP-MS. Due to the many advantages of LIBS, this instrument should be considered a necessity for forensic laboratories.

Identificação e quantificação de resinas, cargas e pigmentos em tintas látex branca

Resins, pigments and fillers constituents in white latex paint were identified and quantified after previous treatment under both low temperature and low pressure in order to get toilet powder from emulsion samples. TG/DTA allowed, under determined conditions, to distinguish the kind of resins, fillers and pigments in commercial paints. X-ray diffractometry was used to confirm the presence of pigment in the final residue from the thermal decomposition.

Calibração de tanques evaporímetros de baixo custo sob diferentes diâmetros em ambiente protegido

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

‘My people right here…’ Indigenous young people, alienation and paint sniffing in inner Brisbane

This paper describes and explains the social worlds of a group of young Murris who are engaged in chroming (paint sniffing) and who sleep rough in inner Brisbane. In particular, the paper considers the ways young Indigenous drug users describe their marginalisation from wider society and its structures of opportunity, but it also includes some reflections from their youth worker and a young man who frequents the young people’s squat. The paper demonstrates the centrality of racism and material disadvantage to the experience of a group of young Aboriginal and Torres Strait Islander sniffers, a perspective largely unreflected in the literature on Indigenous volatile substance misuse. Further, the young people’s ways of interacting with the broader society are described to explain the ways their rejection of mainstream norms form a significant political response to their marginality and reflect, at least in part, the wider Indigenous historical experience. The work draws on theories of alienation and subculture to analyse the young people’s descriptions of their social estrangement and the formation of the ‘paint sniffer group’. It is concluded that paint sniffing among urban Indigenous youth is, at least in part, an obnoxious and encoded distillation of a wider Indigenous rebuttal of broader societal norms, and that the dominant — normalising — modes of treatment risk further alienating an already oppositional group of young people.

Latex allergy : a perioperative environmental hazard

Latex allergy is a serious, possibly life threatening health hazard in the perioperative environment. Policy and procedures should be developed to identify patients who may be sensitive to latex and to ensure the avoidance of latex products in their care. Healthcare workers should also take steps to avoid exposure and protect themselves from hypersensitivity reactions.

Paint spray mass spectrometry for the detection of additives from polymers on conducting surfaces

Paint Spray is developed as a direct sampling ionisation method for mass spectrometric analysis of additives in polymer-based surface coatings. The technique simply involves applying an external high voltage (5 kV) to the wetted sample placed in front of the mass spectrometer inlet and represents a much simpler ionisation technique compared to those currently available. The capabilities of Paint Spray are demonstrated herein with the detection of four commercially available hindered amine light stabilisers; TINUVIN® 770, TINUVIN® 292, TINUVIN® 123 and TINUVIN® 152 directly from thermoset polyester-based coil coatings. Paint Spray requires no sample preparation or pre-treatment and combined with its simplicity - requiring no specialised equipment - makes it ideal for use by non-specialists. The application of Paint Spray for industrial use has significant potential as sample collection from a coil coating production line and Paint Spray ionisation could enable fast quality control screening at high sensitivity.

Influence of kaolinite particle size on cross-link density, microstructure and mechanical properties of latex blending styrene butadiene rubber composites

Cross-link density, microstructure and mechanical properties of styrene butadiene rubber (SBR) composites filled with different particle sized kaolinites are investigated. With the increase of kaolinite particle size, the cross-link density of the filled SBR composites, the dispersibility and orientation degree of kaolinite particles gradually decrease. Some big cracks in filled rubber composites are distributed along the fringe of kaolinite aggregates, and the absorbance of all the absorption bands of kaolinites gradually increase with the increase of kaolinite particle size. All mechanical property indexes of kaolinite filled SBR composites decrease due to the decrease of cross-linking and reduction of interface interaction between filler and rubber matrix.

LaTeX Template for Writing QUT Thesis (Research Masters and PhD)

A LATEX style file, named qutthesis.sty, is developed, for writing PhD or Research Masters thesis. Developed by Professor Glen Yu-Chu Tian, it tries to fulfill QUT’s Thesis requirements but it is unofficial.

Super-plasticized natural rubber latex modified concretes

Polymeric admixtures to concrete ingredients modify the properties of the processed concrete. Ductility is one such property modification. This investigation deals with the development of a method of incorporating natural rubber latex into concrete ingredients with only marginal effects on the compressive strength of base plain concrete. This retention of the strength has been effected by reducing the water/cement ratio with the aid of a superplasticizer. The quantity of natural rubber latex is expressed as the dry rubber content by percentage of volume of concrete. The compressive and tensile strengths, as well as post peak ductile behaviour have been the basis for comparison with those of unmodified concrete.

Dynamic response of latex modified concrete machine foundations

New materials in concrete constructions have been widely used to improve various properties such as impact resistance, strength and durability. Polymer modified concrete is one of the new materials which has been developed for potential application in the construction industry. This Paper describes the use of polymer latex for foundation blocks subjected to dynamic loads. Experiments were conducted using ordinary concrete and latex modified concrete footings of three different thicknesses, for three static loads at four excitation levels. Experimental results have revealed that the amplitude of resonance is reduced considerably in the latex modified concrete footings.

Isolation and characterization of proteolytic enzymes from the latex of Synadenium grantii Hook, 'f'

Two fractions showing proteolytic enzymes have been obtained from the latex of Synadenium grantii Hook, 'f', using gel-filtration and anion-exchange chromatographic techniques. Both these proteases have the same molecular mass of 76+/-2 kDa each. They exhibit maximal activity at pH 7.0 and at a temperature of 60 degreesC. They display stability over a pH range from 5-10 and are also highly thermostable. Irreversible inhibition by PMSF indicates that they are serine proteases. In addition, histidine residues also appear to play an important role in catalysis as evidenced by inhibition with DEPC. They also exhibit similarity with respect to pH and temperature optima, kinetic properties and thermal stability. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

Pressure-sensitive paint on a truncated cone in hypersonic flow at incidences

The flow over a truncated cone is a classical and fundamental problem for aerodynamic research due to its three-dimensional and complicated characteristics. The flow is made more complex when examining high angles of incidence. Recently these types of flows have drawn more attention for the purposes of drag reduction in supersonic/hypersonic flows. In the present study the flow over a truncated cone at various incidences was experimentally investigated in a Mach 5 flow with a unit Reynolds number of 13.5�10 6m -1. The cone semi-apex angle is 15° and the truncation ratio (truncated length/cone length) is 0.5. The incidence of the model varied from -12° to 12° with 3° intervals relative to the freestream direction. The external flow around the truncated cone was visualised by colour Schlieren photography, while the surface flow pattern was revealed using the oil flow method. The surface pressure distribution was measured using the anodized aluminium pressure-sensitive paint (AA-PSP) technique. Both top and sideviews of the pressure distribution on the model surface were acquired at various incidences. AA-PSP showed high pressure sensitivity and captured the complicated flow structures which correlated well with the colour Schlieren and oil flow visualisation results. © 2012 Elsevier Inc.

Plant latex mediated green synthesis of ZnAl2O4:Dy3+ (1-9 mol%) nanophosphor for white light generation

ZnAl2O4:Dy3+ (1-9 mol%) nanophosphors were synthesized by a simple, cost effective and environmental friendly route using Euphorbia tirucalli plant latex. The structural properties and morphological features of the phosphors were well studied by PXRD, FTIR, SEM and TEM measurements. The luminescent properties of ZnAl2O4:Dy3+ (1-9 mol%) nanophosphors were investigated from the excitation and emission spectra. The phosphor performance was evaluated by color co-ordinates. The values were well located in the near white region as a result it was highly useful for the fabrication of green component in WLEDs. The average particle size was found to be similar to 9-18 nm and same was confirmed by TEM and Scherrer's method. The highest photoluminescence (PL) and thermoluminescence (TL) intensity was obtained to be similar to 7 mol% Dy3+ concentration. A single TL glow peak was recorded at 172 degrees C at a warming rate of 2.5 degrees Cs (1). The intensity at 172 degrees C peak increases linearly up to 1 kGy and after that it diminishes. PL intensity was studied with different plant latex concentration (2-8 ml) and highest PL intensity was recorded for similar to 8 ml. The optimized phosphor showed good reusability, low fading and wide range of linearity with gamma-dose hence the phosphor was quite useful in radiation dosimetry. (C) 2013 Elsevier B.V. All rights reserved.