John I. Thornton's research while affiliated with University of California, Berkeley and other places

Publications (43)

Article
A 1986 Federal law regulates the manufacture, importation, and sale of armor piercing ammunition. The external appearance of various types of armor piercing ammunition are described, along with a method of density determination that will assist in distinguishing armor piercing ammunition from conventional ammunition.
Article
Graphite furnace atomic absorption spectrometry was used to determine the concentrations of nickel, iron, and lead in 26 different production lots of Winchester-Western cartridge case brass. In most cases, the measured elemental concentrations were found to be normally distributed within a lot, and the variables lacked any strong association. It wa...
Article
When a firearm is discharged, a complex series of events takes place within an interval of approximately 1 millisecond. Many of these events are associated with chemical as opposed to mechanical processes, and an understanding of these processes, and of the materials involved in these processes, may be of value in the reconstruction of the factual...
Article
Smokeless gunpowder frequently contains diphenylamine as a stabilizer. The diphenylamine acts as a nitrate scavenger and in turn is nitrated by complex processes. The various nitrated congeners of diphenylamine, which are numerous, may serve to characterize a sample of gunpowder because these derivatives reflect not only the production of the gunpo...
Article
A method for reducing specular reflectance from metallic surfaces in which ammonium chloride is used as a fuming reagent is described. This method has the advantage of being easily controlled, and is rapid. The deposit of ammonium chloride salt on the metallic surface is easily and effectively removed by washing.
Article
A κ value represents a type of summary statistic by means of which glass evidence may be interpreted. This statistic is defined as κ = V/D, where the dispersion V = (n(D) - 1)/(n(F) - n(C)), and where D is the density. The κ value is therefore the slope of a line through the 0,0 origin and a plot of dispersion versus density. Obtaining a κ value fa...
Conference Paper
Two fluorescent probes, ANS and TNS, have been further examined for their effectiveness in acting as fluorescent probes for the detection of blood stain patterns. These materials, which are not fluorescent in aqueous solution, react non-specifically with protein and enable an observer to discern a blood pattern when viewed under UV light at 365 nm....
Article
To permit the testing of a number of basic hypotheses regarding the relationship between neighboring minutiae, epidermal ridge minutiae on the distal portions of 412 thumbprints have been surveyed. For each thumbprint a centrally located focal minutia was chosen; neighboring minutiae were then sampled. Minutiae were considered to be neighbors if th...
Article
The dithizone test is frequently used as a color test for lead in the confirmation of projectile wipes. An adjustment of test conditions will also allow the dithizone reaction to be conducted as a microcrystalline test, thereby increasing the specificity of the reaction. The color resulting from the formation of the inner salt complex between dithi...
Article
A descriptive method is presented that allows documentation of minutia configurations in epidermal ridge patterns. The method incorporates the basic features relevant to fingerprint comparison: minutia types, orientations, and relative positions. Provision is also made for the ambiguities in minutia type which are an inevitable feature of any finge...
Article
A critical analysis is presented of the seven principal models previously proposed for the quantitative assessment of fingerprint individuality. Although these models have been developed over a long period of tome, there has been no systematic or comprehensive review of all seven models; indeed, two very significant models have escaped the attentio...
Article
Shotgun pellet dispersions were measured by using a shotgun with the following parameters being varied: barrel length, discharge distance, choke constriction and shot size. To reduce the number of experiments the statistical technique of Greco-Latin squares was used. A full statistical analysis of the data carried out and possible correlations betw...
Article
Conventional attitudes within the forensic science community concerning the fracturing of glass center around tensile failure of the glass, frequently depicted as a 'bending' of the glass. While this is not conceptually incorrect, it represents only one case of a more universal phenomenon in which the tensile failure of glass does not necessarily i...
Article
Intuitively, a hand held in close proximity to a firearm at the instant of discharge will intercept a significant amount of gunshot residue, even though the hand did not actually come into contact with the weapon. There is, however, little information specifically described in the forensic science literature concerning the residue levels which migh...
Article
It was determined that tempered glass automobile windows may severely influence the trajectory of .38 Special projectiles. In replicating an actual case situation, deflections as great as 26.4 degrees were observed with jacketed hollow-point ammunition, and as high as 10.8 degrees for lead ammunition.
Article
Graphical representation of glass density versus refraction index data have classically been in the form of two-dimensional scattergrams. For the purpose of illustrating how common or uncommon a particular glass sample is, a three-dimensional projection graph has been found to be useful.
Article
Ensembles of class characteristics resulting from indifferent quality assurance in manufacturing technique may legitimately transcend conventional attitudes concerning class characteristics. Ensembles of these sublcass characteristics converge on individual characteristics. This is illustrated using the data describing Titan .25-caliber automatic p...
Article
The type of device commonly referred to as a "starlight scope" will amplify available light by a factor of approximately 17 000. The use of this device will permit an image to be formed by exceedingly small amounts of blood when reacted with luminol reagent. Modification of the apparatus is necessary to permit focusing at short distances.
Chapter
Soils do not simply “exist.” They are formed, and they are maintained. Soil environments, and by extension soils in general, are unique because of the unlikeliness of the replication in all respects of the processes involved in the formation of the soil, and the impossibility of replication of the processes involved in the maintenance of the soil e...
Article
The high correlation of density and refractive index has tended to obscure certain aspects of the interpretation of glass evidence. The fundamental relationship of the two properties are examined here from the standpoint of composition and heart treatment, and considerations which may lead to conceptual errors in the interpretation of provenance ar...
Article
Regression analysis and analysis of covariance demonstrates (1) a high correlation between glass density and refractive index and (2) continuity in the regression line throughout the entire range of glass density values. Once a refractive index value is obtained, reference to the regression line will provide an approximate density value, knowledge...
Article
Ninhydrin is observed to differentiate among common phenethylamines of abuse. Amphetamine, methamphetamine, mescaline and STP may be easily distinguished. Colors given by phenethylamines are presented with their corresponding Munsell and ISCC–NBS values.
Article
A discussion is presented of the forensic interpretation of annealed glass fracture. The processes of glass fracture are given, the nature and formation of glass as a brittle isotropic solid is discussed, and the mechanical strength of glass is considered in terms of its atomic bond strengths and external flaws. Major modern theories of glass fract...
Article
Phenethylamines of forensic or toxicological interest can be resolved by high pressure LC, either by ion-exchange or adsorption techniques. Ion-exchange chromatography on DA-X4 was found to provide the most suitable separations. Adsorption chromatography on Corasil II was found to provide adequate separation of common phenethylamines, but recourse...
Article
Substituted hydantoins, a number of which possess anticonvulsant activity and are prescribed alone or compounded with barbiturates, were observed to enter into a number of reactions commonly utilized to identify barbituric acid derivatives. The reactivity of the hydantoins with the Dille-Koppanyi and the Zwikker tests is sufficiently similar to tha...
Article
A number of plants similar in appearance to marijuana (Cannabis sativa) were examined using the scanning electron microscope. This information may be of assistance in identifying marijuana in routine investigations using the optical microscope.
Article
A new method is described for the separation, tentative identification and quantitation of Heroin, 06-Monoacetylmorphine HCl (6-MAM HCl) and Morphine utilizing high pressure liquid adsorption chromatography. The analysis is rapidly performed, requires little sample preparation, provides two independent criteria for identification, and the separated...
Article
A reliable method is described for the extraction of unchanged ibogaine from biological materials such as blood, urine, and tissue homogenates of liver, kidney, and brain by a simple extraction for basic drugs. Precise identification of the alkaloid may be achieved through the use of thin-layer chromatography, ultraviolet and infrared spectrophotom...
Article
A number of instances have arisen in which the seeds of the plant Argyreia nervosa, a tropical wood rose, have been ingested for their content of psychotomimetic alkaloids, tentatively identified as lysergic acid amide and related substances. A botanical description of the plant is given, together with data relating to the thin-layer chromatographi...
Article
A recently developed weapons system is described, along with operating details and identification notes. The projectile utilized in the system described is a spin-stabilized rocket fired through a smooth bore. Identification of a fired projectile as having been fired from a particular weapon may be effected with relative ease through a comparison o...
Article
A simple technique for the identification of the Opium Poppy is described. The principal alkaloids are extracted from the plant by boiling water and identified by thin-layer chromatography in a benzene, dioxane, ammonium hydroxide, ethanol solvent. Approximately one hour is required for the extraction and identification of the alkaloids with a sens...

Citations

... Further discrimination may be achieved by the comparison of the chemical composition of the topcoats. The chemistry of paint can be determined using microchemical spot tests (7,8), infrared spectroscopy (1)(2)(3), elemental analysis (9,10), and pyrolysis-gas chromatography (11)(12)(13). ...
... Dear Sir: In reply to Dr. Sperber's letter, I refer to page 1239 of the article under discussion [1]. The authors describe a bite mark impression technique in which impression material sets completely, is covered with orthopedic tape and then with another layer of impression material. ...
... It is particularly striking that, despite the use of dactyloscopy for more than a century, articles that have provided information on the variability of the minutiae are so few. In addition, most of them study fingerprint samples from males, and vary considerably both in the sample size (such as the fingers selected for analysis) and the types of minutiae valued [23][24][25][26][27][28][29][30][31][32][33][34][35]. ...
... Spitz (2006) proposed that beveling could assist in identifying the angle of fire. Several experimental studies for gunshots have reported that beveling usually occurs on the opposite side of the original direction of the bullet (Thornton and Cashman 1986). And beveling on the exit wound would usually present along the direction of the moving track of the bullet when penetrating the bones (DiMaio 1998). ...
... Forensic analysis of glass has typically been based on refractive index, dispersion and density analyses. 76 In 1991, the statistical discrimination of flat glass by neutron activation analysis of the sample's elemental composition was demonstrated. 77 The determination of up to 70 elements by ICP-MS was later demonstrated. ...
... So far dithizone, zincon and chlorindazone DS have been tested for effectiveness. Dithizone [4,5] is a method that could be applied when the items of evidence are exclusively treated in a forensic science laboratory. It was necessary Volume 35, Number 2 to transfer the GSR from the targeted object onto photo paper as secondary matrix in order to guarantee a reproducible visualization. ...
... If approximately half of the experts viewing a particular minutia state that it is clearly a ridge ending, and approximately half of the experts viewing the same minutia state that it is clearly a bifurcation, there is de facto connective ambiguity (as defined by Stoney and Thornton [27]) to the minutia. It does not necessarily follow that these ambiguities only occur in low quality marks, or in degraded local areas within otherwise clear marks. ...
... Moreover, it is assumed that the projectile is fired horizontally at an initial height of 1.7 m measured from the floor, disregarding the dispersion due to the transmitted momentum of the other pellets. Other studies [25][26][27] detail essential considerations to understand various dispersion models of cartridge bullets fired to multiple distances. It should also be noted, regarding the time of the phenomena description, that all the analyses concern the time taken from the exit of the shotgun riot to the target, leaving aside the physical aspects when the bullet is inside the barrel. ...
... several households such as window panes, bottles, etc. are made of glass (Nadarajan et al., 2020). Since, the evidential value of glass has been described by several researchers (Mcjijnkins and Thornton, 1973;Stoney and Thornton, 1985;Curran et al., 2000;Caddy, 2001;Copley, 2001;Gogotsi and Mudrik, 2010). The brittle nature of glass also poses a number of complications. ...
... It is particularly striking that, despite the use of dactyloscopy for more than a century, articles that have provided information on the variability of the minutiae are so few. In addition, most of them study fingerprint samples from males, and vary considerably both in the sample size (such as the fingers selected for analysis) and the types of minutiae valued [23][24][25][26][27][28][29][30][31][32][33][34][35]. ...