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Your search keyword '"Particle-size distribution"' showing total 6 results
Start Over Descriptor "Particle-size distribution" Journal journal of forensic sciences
6 results on '"Particle-size distribution"'

1. Developing and Testing a Soil Property Database for Forensic Applications in Southern California.

Author

Menchaca, Patricia R., Graham, Robert C., and Younglove, Theodore

Subjects
*DISCRIMINANT analysis, *FORENSIC sciences, *SOIL color, *SOIL testing, *PARTICLE size distribution, *MAGNETIC susceptibility
Abstract

Abstract: The research sought to develop and test a forensic database of surface soil variability within previously mapped geologic and soil units in southern California. This type of database could be used to link suspects to crime scenes or determine source locations of soil sample evidence. Variability was evaluated using (i) color, (ii) magnetic susceptibility, and (iii) particle‐size distribution. Soil properties were analyzed for their ability to discriminate source areas using stepwise discriminant analysis. The percent correct predictions for geologic unit groups ranged from 30% to 100%. A blind study experiment matched four of the 18 samples to their unit of origin with the first choice by stepwise discriminant analysis, and eight were matched as second and third choices. The probability of selecting the appropriate unit of origin increased by 54% over random chance and eliminated as much as 99% of the field area as a potential search location. [ABSTRACT FROM AUTHOR]

Published
2018
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2. Comparative Forensic Soil Analysis of New Jersey State Parks Using a Combination of Simple Techniques with Multivariate Statistics.

Author

Bonetti, Jennifer and Quarino, Lawrence

Subjects
*MULTIVARIATE analysis, *FORENSIC sciences, *DISCRIMINANT analysis, *PARTICLE size distribution, *SOIL testing
Abstract

This study has shown that the combination of simple techniques with the use of multivariate statistics offers the potential for the comparative analysis of soil samples. Five samples were obtained from each of twelve state parks across New Jersey in both the summer and fall seasons. Each sample was examined using particle-size distribution, p H analysis in both water and 1 M CaCl2, and a loss on ignition technique. Data from each of the techniques were combined, and principal component analysis ( PCA) and canonical discriminant analysis ( CDA) were used for multivariate data transformation. Samples from different locations could be visually differentiated from one another using these multivariate plots. Hold-one-out cross-validation analysis showed error rates as low as 3.33%. Ten blind study samples were analyzed resulting in no misclassifications using Mahalanobis distance calculations and visual examinations of multivariate plots. Seasonal variation was minimal between corresponding samples, suggesting potential success in forensic applications. [ABSTRACT FROM AUTHOR]

Published
2014
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3. A systematic study to understand the effects of particle size distribution of magnetic fingerprint powders on surfaces with various porosities

Author

Serkan Gürbüz, Bahar Özmen Monkul, Merve Gürtekin Seden, Melek Erol, and Tuğba İpeksaç

Subjects
Materials science, Mixing (process engineering), Analytical chemistry, Surface finish, Pathology and Forensic Medicine, law.invention, chemistry.chemical_compound, chemistry, Optical microscope, law, Particle-size distribution, Genetics, Fingerprint powder, Particle size, Composite material, Magnetite
Abstract

This study intends to design magnetite (Fe3 O4 )-based magnetic fingerprint powders with different particle size distributions. It also investigates the influence of particle size distribution on the visualization of latent fingermarks with as little background staining as possible on the surfaces with various porosities in a systematic way. Two strategies were used to prepare the magnetic fingerprint formulations for this study: milling of coarse magnetite particles for different durations, and mixing of sieved fine particles with different size ranges with coarse particles. Particle size analyses of the prepared magnetic powders, optical microscopy-based roughness analysis of the surfaces and SEM measurements of the visualized fingerprints and representative powders were performed. Mag2 of the formulations prepared through milling and Mag5 and Mag6 of the formulations prepared through sieving and mixing were more successful in the development of latent prints than the rest of the solutions.

Published
2013

4. Discrimination of Ceramics—Study on the Microstructures of Ceramics

Author

Shigehito Deki, Takashi Hashimoto, and Yukio Kanaji

Subjects
Diffraction, Materials science, Scanning electron microscope, Metallurgy, technology, industry, and agriculture, Analytical chemistry, equipment and supplies, Microstructure, Grain size, Pathology and Forensic Medicine, Microcrystalline, visual_art, Etching, Particle-size distribution, Genetics, visual_art.visual_art_medium, Ceramic
Abstract

A method for discrimination of alumina ceramics was developed based on the observation of the surface morphology of etched surfaces, density, X-ray diffraction line profiles and grain size distributions. The experimental observations of the surface microstructure were made, using the scanning electron microscopy (SEM), on several different alumina ceramics with high (>99%), middle (96 to 98%) and low (approximately 92%) alumina content in order to identify them. The samples were prepared with a sulfuric acid (4.5 mol/L) etching method performed at 150 ≈ 200°C for 2 h on low and middle purity alumina ceramics and for 4 h on high purity alumina ceramics. The results indicate that the SEM observation coupled with computerized image analysis to determine grain size distribution is a powerful tool to discriminate among alumina ceramics that exhibit similar morphological characteristics. The X-ray diffraction line profile study is suggested as an additional useful index for the determination of microcrystalline structure.

Published
1994

5. Sampling Errors in the Determination of Cocaine in Seized Drugs

Author

Barbara Brown and Byron Kratochvil

Subjects
Chromatography, Sample Weight, Sample (material), Particle-size distribution, Genetics, Sampling (statistics), Sampling error, Gas chromatography, Diluent, Standard deviation, Pathology and Forensic Medicine, Mathematics
Abstract

Experiments in which 28-g (1-oz) seizures of cocaine plus diluent (mannitol, inositol) were ground in a mortar for only a few minutes before removal of 20-mg portions for assay (by gas chromatography using bupivicaine as internal standard) showed the standard deviation of the sampling operation to be several times larger than the standard deviation of the analytical operations. Measurement of the particle size distribution of ground mixtures allowed estimation of the weight of sample required to lower the sampling standard deviation to any specified level. The sample weight required was shown to depend in a predictable way on the percentage of cocaine present in the material.

Published
1984

6. Determination of Particle Size Distribution of Soils in Forensic Science Using Classical and Modern Instrumental Methods

Author

B. Caddy, S. Wanogho, George Gettinby, and James Robertson

Subjects
Diffraction, Soil test, Chemistry, Sample size determination, Coulter counter, Soil water, Particle-size distribution, Genetics, Wet sieving, Mineralogy, Pathology and Forensic Medicine, Characterization (materials science)
Abstract

Wet sieving, laser diffraction, Coulter counting, and microscopical image analysis are compared as particle size distribution methods for the characterization of soil samples. The influence of the sample size on the distribution and the problem of choosing representative samples from small amounts of soil are highlighted.

Published
1989

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