Charles S. Tumosa

A blue encrustation found on skeletal remains of americans missing in action in Vietnam

A blue encrustation was found on the repatriated remains of three U.S. Servicemen listed as missing in action (MIA) from Vietnam after 28 years. The identification and origin of the blue material was determined. Scanning electron microscopy with energy dispersive analysis and powder X-ray diffraction identified the material as the mineral vivianite, Fe3 (PO4)2.8H2O. Vivianite has been found often associated with fossilized bone and teeth, but this example is unusual in that it is only the second published forensic example of vivianite growing from human bone after such a short period of time. The presence of vivianite provides information leading to a more complete and accurate understanding of the taphonomic process associated with American MIA remains.

INVESTIGATION INTO THE DETERIORATION OF PAINTINGS AND PHOTOGRAPHS USING COMPUTERIZED MODELING OF STRESS DEVELOPMENT

AbstractThe environmental effects of temperature and relative humidity on the mechanical response of paintings and photographs were examined using numerical methods and computer analysis. The basic mathematical approach is introduced that defines the material parameters necessary to conduct such an analysis. Methods of determining the material and dimensional properties of materials with comments on the effects of increasing measurement. accuracy are discussed. Using measured material properties for paintings and photographs, complete computer analyses were conducted that modeled the physical response to changing temperature and relative humidity. The calculated results were compared to experimental test specimens subjected to similar environmental variations.

The influence of lead ions on the drying of oils

Abstract Lead compounds or pigments alter the drying behavior and physical properties of oil paints and varnishes, enabling artists and craftsmen to tailor the properties most suited for their purposes. Investigations into the mechanism of these changes have, however, often been contradictory or misleading. Using modern theories of driers, the behavior of lead additives or pigments can be interpreted or classified.

The changing mechanical properties of aging oil paints

The stiffening and embrittlement of oil paints over time has been a real concern for those responsible for the long term care and preservation of paintings. This paper examines the effects of time, pigments, relative humidity (RH), temperature and solvents on the mechanical properties of traditional oil paints. In this way it is possible to determine the role of each factor in causing the paints to become brittle. Even after 14 years the oil paints show little evidence that the long term “maturing” processes have begun to slow down. It is shown that there seems to be little correlation between the time paint requires to “dry-to-the-touch” and the longer term mechanical properties. Both low and high temperature levels can increase the stiffness of the paints though the mechanisms are quite different. Considerable hydrolysis of the paints occurs early in their history and the ones that hydrolyze most quickly are the ones that remain the most flexible.

A lectin in the pollen of marihuana, Cannabis sativa L.

A lectin was found in the pollen ofCannabis sativa L. which reacted with papain treated erythrocytes. The lectin has an affinity for glucose containing receptor sites.

Linseed Oil Paint as Ionomer: Synthesis and Characterization

As linseed oil ages, hydrolysis and oxidation produce acid groups on the polymer chain that may lead to ionomeric behavior. The effect of these changes is difficult to determine in old paints because of the lack of records of environmental and treatment histories that can alter the physical properties significantly. A series of paints were made that have chemical properties similar to those of aged paints and that mimic old paints. Their properties seem to show flexibility as well as coherency but low strength and a high susceptibility to solvents.

A General Model Relating Externally Applied Forces to Environmentally Induced Stresses in Materials

The structural degradation effects of temperature (T) and relative humidity (RH) are important considerations in the setting and maintaining of museum environments. An approach to determining the acceptable values for this environment would be useful if a general model could be developed from simple physical (mechanical) measurements. In this article, a general model is developed in which the mechanical behavior of materials composing museum objects can be described using the easily determined parameters, stress development (force), environmental conditions, and dimensional change. -- AATA

The reaction of human anti-A and anti-B sera with animal bloodstains

SummaryThe reaction of animal bloodstains with human anti-A and anti-B typing sera was examined by absorption-elution. The majority of samples studied reacted with either one or both sera. The results demonstrate the need for precise species determination in forensic work.ZusammenfassungEs wird über die Reaktion von Tierblutflecken auf A- oder B-Antikörper mittels Absorption-Elution berichtet. Die Mehrzahl der Fälle manifestierte sich wie menschliche A-, B- und AB-Gruppen.