Morphological Variations of Explosive Residue Particles and Implications for Understanding Detonation Mechanisms

The possibility of recovering undetonated explosive residues following detonation events is well known, however, the morphology and chemical identity of these condensed phase post-blast particles remains undetermined. An understanding of the post-blast explosive particle morphology would provide vital information during forensic examinations, allowing rapid initial indication of the explosive material to be microscopically determined prior to any chemical analyses, and thereby saving time and resources at the crucial stage of an investigation. In this study, condensed phase particles collected from around the detonations of aluminized ammonium nitrate and RDX-based explosive charges were collected in a novel manner utilising SEM stubs. By incorporating the use of a focused ion beam during analysis, for the first time it has been possible to determined that such particles have characteristic shapes, sizes and internal structures depending on the explosive and the distance from the detonation at which particles are recovered. Spheroidal particles (10 µm to 210 µm) with micro surface features recovered following inorganic charge detonations were dissimilar to the irregularly shaped particles (5 µm to 100 µm) recovered following organic charge firings. Confirmatory analysis to conclude the particles were indeed explosive included HPLC-MS, Raman spectroscopy and MeV-SIMS. The results impact not only on forensic investigation but also on the theoretical constructs which govern detonation theory by indicating the potential mechanisms by which these particles survive and how this varies between the different explosive types

The Spatial Distribution of Post-blast Condensed Phase Explosive Residues

During bomb scene investigation the collection of trace explosive residue is a principal forensic task which allows the cause of the explosion to be determined. However the optimum locations around a detonation from where these undetonated trace residues should be sampled has not been determined scientifically. Crime scene investigation guides describe several methods for collecting and analysing explosive residues, but literature regarding the most efficacious areas to sample from is relatively scarce. In this thesis, analysis of the spatial distribution patterns of post-blast explosive residues from detonation and simulation experiments with 0.5 kg, 1 kg and 2 kg aluminised ammonium nitrate and RDX composition charges are the primary original contributions to the literature. Residue samples were collected by swabbing sample sites positioned around the explosive charges and condensed phase particles were collected onto smaller sample sites in order to ascertain the physical morphology of the residues. Both organic and inorganic residues ultimately decreased in concentration nonlinearly with increasing distance from the charge centre. However, the distribution trends between different explosive analytes varied, suggesting the dispersal mechanisms or factors which affected the distribution for each were different. The post-blast particles had varying morphologies at different distances from the detonation and also exhibited different features based on the explosive type. Computational simulations of residue distributions compared well to the experimental results; substantiating the capability of numerical methods to be used as a forensic investigation aid. The key findings from this thesis have provided empirical evidence which validates the current forensic practice of concentrating trace evidence collection near the central region of a detonation area during bomb scene investigation. The findings also imply that surfaces which are downwind of the detonation should be focused on for residue sampling and that microscopic examination of items in the vicinity of a detonation may allow identification of the explosive used based on particle morphology, prior to any chemical analyses. Furthermore, having demonstrated the reliability and capability of simulation techniques to model explosive residue distribution, these can now be developed and validated through further tests which also assess the detonations of further explosives under different conditions

Sustaining traditional food: consumers' perceptions on physical characteristics of keropok lekor or fish snack

Keropok Lekor or frankfurter-like snack has long existed in Malaysia and has been sold in commercial retail shops as well as on the streets. The aims of this study were to analyze consumer's perception and attitude towards keropok lekor and to determine consumer's behavior on the product. Survey questionnaire was employed as a data collection tool. A total of 212 respondents from a university participated in this study. Results showed that more than 70% of the respondents chose to eat keropok lekor because of the taste. Half of the respondents chose black pepper as an innovative supplementary flavor of keropok lekor. This study also explores and analyses preliminary consumer behavior about keropok lekor such as satisfaction level, factors that drive consumption, product's image from consumer perspectives and etc

OPTIMIZATION AND CHARACTERIZATION OF PEG-PCL-PEG TRIBLOCK COPOLYMER AS CARRIER OF DRUG USING FULL FACTORIAL DESIGN

Objective: Triblock copolymer of poly(ethylene glycol)-poly(ɛ-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) was applicated as hydrophobic drug. This study aims to optimization and characterization of PECE triblock copolymer as carriers of hydrophobic drug (ketoprofen). Methods: Triblock copolymer of PECE was prepared with varying composition ratio of PEG and PCL by ring-opening and coupling reaction. The characteristics of triblock copolymer were characterized using FTIR and DSC. Variation composition ratio of poly(ɛ-caprolactone) (PCL)/poly(ethylene glycol) (PEG) and ratio PECE/drug as factors for optimization using full factorial design. Ketoprofen was loaded into PECE triblock copolymer micelles by emulsification and solvent evaporation method. Responses were measured particle size, entrapment efficiency (EE) and drug solubility. Results: The result of this study showed that a higher ratio of PCL/PEG and ratio of PECE/drug, reducing particle size, increasing EE and improving drug solubility. The optimum formula obtained by ratio of PCL/PEG is 2:1 and ratio of PECE/drug is 40:1 with particle size is 356,967±9,142 nm, EE is 57,751±0,437%, drug solubility is 32,648±0,200 µg/ml and zeta potential-18,867±2,578 mV. A full factorial design was applied to determine the optimum formula for the PECE triblock copolymer as drug carriers. Conclusion: The PECE triblock copolymer was preparated using ring-opening polymerization method with Sn(Oct)2 as a catalyst and then continued the reaction with HMDI as coupling agent. Ketoprofen was loaded into PECE triblock copolymer using methods emulsification and solvent evaporation

Effect of sago and tapioca starches on the physicochemical and textural properties of expanded rice product coloured with red beetroot (Beta vulgaris) powder

Colour plays an important role in food especially in increasing the aesthetic value of food products. However, the increasing awareness on health implications of synthetic colourants has led to increased market for natural colourants. In this study, the retention of colourant from red beetroot powder in extruded rice flour containing 20% sago or tapioca starch was investigated. The moisture content of the rice flour-starch blends and 100% rice flour (control) was adjusted to 10% and the samples were extruded at 80ºC - 160ºC, with 120 rpm screw speed and 40 rpm feeder speed. The expansion, density, water absorption index (WAI), water solubility index (WSI), hardness, crispness, colour, and betanin content of the extrudates were measured. The results showed that rice flour-sago starch extrudates (RSE) and rice flour-tapioca starch extrudate (RTE) had better expansion compared to the control (100% rice flour) extrudate. The expansion of RTE was not significantly different from that of RSE and no significant difference was found in the densities of these two extrudates. Presence of sago or tapioca starch decreased the WAI and increased the WSI of the extrudates. The WAI of RSE, however, did not differ significantly from that of RTE. The hardness (18.37 kg) and crispness (126.55 kg.sec) of the control extrudate were higher than that of the RSE (16.97 kg, 110.07 kg.sec) and RTE (14.84 kg, 92.77 kg.sec). There was no significant difference between the redness values of the extrudates. However, retention of betanin in the extrudates was highest in RTE (36.06% retention), followed by RSE (34.14%) and lowest in the control extrudate (27.82%). Addition of tapioca starch or sago starch can help to improve the physical and textural properties of betanin coloured rice extrudates with tapioca starch giving higher betanin retention

A new constant market share competitiveness index

Constant-market-share analysis (CMSA) is one of the most widely employed descriptive tool for measuring the export competitiveness of a country relative to other countries or regions of trade for goods and services. Typically, export growth is attributed to growth in the country’s export competitiveness and also to the growth effect of the market itself. However, CMSA measurement is prone to a number of methodological short comings which stems from the CMS identities used in the analysis. Namely, the discrete approximation of continuously changing trade patterns, the interaction effects term residual from the CMS identity decomposition and the arbitrary choice of weights attached to base periods. This paper addresses some of the short comings of the classic CMSA approach. Within a geometric framework we reexamine the CMS decomposition and propose a new net-share approach that is easier to implement and interpret. For researchers and policy makers, this methodology presents a simpler but more consistent measurement for more accurate CMS measurement and interpretations of changing trade patterns

METHOD VALIDATION OF SIMVASTATIN IN PCL-PEG-PCL TRIBLOCK COPOLYMER MICELLES USING UV-VIS SPECTROPHOTOMETRIC FOR SOLUBILITY ENHANCEMENT ASSAY

Objective: This study aims to increase the solubility of simvastatin (SIM), a hydrophobic drug, by incorporating it into PCL-PEG-PCL triblock copolymer micelles and validating the assay method used, namely Uv-Vis spectrophotometric. Methods: The shake flask method was used to determine the increase in solubility experienced by SIM after being incorporated into the micellar system. The values ​​of maximum wavelength (λmax), linearity, LOD, LOQ, accuracy, and precision were used as parameters measured to assess the validity of the assay method used. Results: The results showed that PCL-PEG-PCL triblock copolymer micelles could increase SIM solubility by 9.7 times (89.49±5.75 µg/ml) compared to SIM without modification (9.19±0.24 µg/ml). The validation results show the λmax value of 239 nm, a linear calibration curve with an R-value of 0.9994, LOD and LOQ of 0.33 µg/ml and 1.00 µg/ml, accurate measurement with recovery at concentrations of 80%, 100%, and 120% were 102.93±1.32%, 100.78±0.40%, and 104.58±0.79% and also had good precision ​​with RSD<2%. Conclusion: The PCL-PEG-PCL triblock copolymer micelles can increase SIM solubility and the Uv-Vis spectrophotometric method has been validated successfully for the quantitative analysis of SIM in PCL-PEG-PCL triblock copolymer micelles

Quality assessment of ozone-treated citrus fruit juices

The aim of the present work was to analyse the impact of ozone treatment on the physicochemical parameters and antioxidant capacity of citrus fruit juices (orange, lemon and lime) with different juice components (total soluble solids). Each sample was ozonated at different ozone treatment time, between 0 to 30 min with fixed ozone concentration of 600 mg/h. The synergistic effects of ozone treatment and the different types of juice were found to significantly affect the pH, total colour difference (TCD), pectin methylesterase (PME) activity, ascorbic acid (AA) and total phenolic content (TPC) of treated juices, while total soluble solids, turbidity and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay were found to be unchanged. It was observed that PME activity decreased with treatment time and this is related to the decrease of juice turbidity (R2 = 0.86) and TCD (R2 = 0.78). Ascorbic acid showed an abrupt decrease in all the juices especially in orange juice with percentage loss of 85%. TPC also showed decreasing trend for all juices with maximum loss of 84.4% in lemon juice after 30 min of ozonation time. The present work also found that lemon juice could retain most of its antioxidant activities (DPPH 98.9%, TPC 96%, AA 86.7%) after 10 min of ozone treatment time in comparison to orange and lime juices

An efficient metal-free hydrophilic carbon as a counter electrode for dye-sensitized solar cells

This study presents a new cost-effective metal-free counter electrode (CE) for dye-sensitized solar cells (DSSCs). CE was prepared by doctor blading a hydrophilic carbon (HC) particle on a fluorine-doped tin oxide substrate. Thereafter, HC CE was characterized using X-ray diffraction, profilometry, four-point probe testing, and cyclic voltammetry. A 2 μm thick HC CE revealed a comparable catalytic activity to that of the Pt electrode under the same experimental conditions. DSSC based on HC CE was analyzed and showed J s c of 6.87 mA/cm2 close to that of DSSC with Pt CE (7.0 mA/cm2). More importantly, DSSC based on HC CE yielded a power conversion efficiency (η) of 2.93% under AM 1.5 irradiation (100 mW/cm2), which was comparable to that of DSSC based on standard Pt CE. These findings suggest that HC CE could be a promising CE for low-cost DSSCs

Adaptive iterative dose reduction (AIDR) 3D in low dose CT abdomen-pelvis: effects on image quality and radiation exposure

The widespread use of computed tomography (CT) has increased the medical radiation exposure and cancer risk. We aimed to evaluate the impact of AIDR 3D in CT abdomen-pelvic examinations based on image quality and radiation dose in low dose (LD) setting compared to standard dose (STD) with filtered back projection (FBP) reconstruction. We retrospectively reviewed the images of 40 patients who underwent CT abdomen-pelvic using a 80 slice CT scanner. Group 1 patients (n=20, mean age 41 ± 17 years) were performed at LD with AIDR 3D reconstruction and Group 2 patients (n=20, mean age 52 ± 21 years) were scanned with STD using FBP reconstruction. Objective image noise was assessed by region of interest (ROI) measurements in the liver and aorta as standard deviation (SD) of the attenuation value (Hounsfield Unit, HU) while subjective image quality was evaluated by two radiologists. Statistical analysis was used to compare the scan length, CT dose index volume (CTDIvol) and image quality of both patient groups. Although both groups have similar mean scan length, the CTDIvol significantly decreased by 38% in LD CT compared to STD CT (p<0.05). Objective and subjective image quality were statistically improved with AIDR 3D (p<0.05). In conclusion, AIDR 3D enables significant dose reduction of 38% with superior image quality in LD CT abdomen-pelvis