Forensic science incorporates many different scientific disciplines: criminalistics, toxicology, pathology, entomology, engineering, psychology, accounting, etc. Criminalistics incorporates such diverse areas as crime scene investigation, sexual assault evidence, DNA analysis, firearms identification and comparison, drug analysis, impression evidence, and trace evidence.

A variety of microscopes and microscopical techniques are used to answer “real world” questions about physical evidence in criminalistics. The microscopes most often used include stereo (dissecting), biological (brightfield), polarizing light, phase contrast, fluorescence, transmitted light comparison, reflected light comparison, and scanning electron. Additionally, detectors from different areas of the electromagnetic spectrum have been added to microscopes to enhance the information obtained from a specimen: infrared, visible-ultraviolet, and x-ray. to gather more information about the specimen with visible light microscopes, dispersion staining(1), contrast enhancement techniques(2) fusion methods(3), chemical staining(4), and micro-chemical tests(5,6) can be integrated into the analytical scheme.

The economic importance of animal hides and skins as the source material for the natural leather industry is significant world-wide, and in some countries of the developing world the livelihood of a large proportion of the population depends upon it. Consequently, it is understandable that anything affecting the quality of the source material and the finished product has major economic, industrial and sociological significance. It is also inevitable that a product that is so widely-used in many ways by most of the population will become an important source of evidence in forensic investigations.

Quality control procedures in the leather industry involve monitoring the progress of the hides and skins from the growth stages of the animal, through the slaughter, storage, transportation, curing, tanning and finishing processes, to the sale and distribution of the finished product. There are many factors during these stages that can affect quality of finished leather, amongst the most important of which are mechanical and parasite damage during growth, biodeterioration and mechanical damage between slaughter and curing, mechanical, heat and chemical damage during curing, tanning and finishing.

Fiber cement roofing shingles from condominiums in Hawaii were examined for deterioration using optical and scanning electron microscopy. The product has a 50 year warranty and had been in service since 1994. Shingle samples were taken in August and September, 2000 after a growing volume of reports of roofing deterioration were received by the condominium association. Close-up visual inspection confirmed that the roof areas showing deterioration were covered with a black growth. Roofing samples from areas exhibiting deterioration, areas with no deterioration, and new material were compared by microscopy.

Examination of the black growth by optical microscopy revealed it to be primarily the Cyanobacterium, Scytonema sp.This is a filamentous organism found from the Arctic to the Antarctic, and is common to Oahu and Maui.’ Other organisms observed to be present are Chroococus sp., Gloeocapsa sp., Aphanocapsa sp., Oscillatoria sp.,a very few Trebouxia sp.and lichens.

The rapid rise of energy costs in the 1970's and early 1980's brought about a number of energy conservation measures which are still in use today. Changes made in heating, ventilating and air conditioning (HVAC) systems increased the recirculation of conditioned air within buildings, while leakage of air through the building shell was sharply reduced. Air movement in modern buildings is typically under the control of centrally operated HVAC systems which do not allow for local control of airflow in particular areas by the occupants. Problems with the quality of indoor air in the work environment have resulted from some of these measures and collectively many of these phenomena have been referred to as the Sick Building Syndrome (SBS). SBS is a complex of symptoms, including eye and mucous membrane irritation, headache, cough, dizziness, chest tightening, fatigue and general malaise, which occur more frequently than would normally be expected (greater than 20%) among the occupants of a building.

Indoor air quality concerns are becoming increasingly important in the United States as a result of a greater awareness of the harm fungi can cause to structures and the people living in those structures. By making our homes and offices more energy efficient and by making heating and ventilation systems more complex we have also created some indoor air quality problems.

Microscopical indoor air investigations are growing rapidly as evidenced by the number of asbestos and other labs getting into the fungal spore identification business. Many companies are growing by 20% a month and cannot find enough qualified microscopists to perform the identification of the fungi..

There is a real need to revitalize the teaching of light microscopy to solve indoor air problems. Fungal spores and pollen are the common culprits that cause indoor air quality problems that can be studied with the light microscope. with proper training, an indoor air quality investigator can make better use of their elegant analytical tool, viz.

Atmospheric aerosols are often investigated in order to gain insight into their effects on the global radiative heat budget, optical properties of the atmosphere, and their effects on human health. Characterizing the seasonal behavior of these aerosols is fundamental in understanding their climatological and air quality impacts. As part of a larger program to study the present and recent history of chemical species transported to Greenland, we analyzed a seasonal cycle of total aerosol matter scavenged from the air by surface snow.

During a “winter-over” experiment in Summit, Greenland, extending from June 1997 through March 1998, kilogram quantities of surface snow were collected, melted, and filtered onto high-purity quartz fiber filters in the field. Upon the receipt of these filters at NIST, the total particulate matter was removed from the filters and transferred to boron substrates with protocols involving resuspension, centrifugation, and filtration.’ Previous techniques that quantified multi-element particles used several different substrates.

The Indian Ocean Experiment (INDOEX) was conducted in Feb.-Mar. 1999 in a large area of the Indian Ocean, Bay of Bengal, and Arabian Sea to investigate climate forcing produced by pollutant aerosol particles being transported out of India, Pakistan, and Indochina during the Northeast (“Dry“) Monsoon2. Pollutant aerosols can be transported a thousand km or more by prevailing winds as far south as the Inter-tropical Convergence Zone (ITCZ), the convective band that separates Northern and Southern Hemisphere tropospheric air. We present here results from TEM examination of aerosol particles collected on INDOEX research flights of the NCAR C-130 aircraft.

The climate forcing properties of sulfate aerosols over the oceans have long been recognized2. Sulfate and other particles scatter incoming solar radiation, reducing the amount of light (and heat) incident on the ocean surface and thus causing a cooling effect which may locally counter some of the warming effect due to greenhouse gases.

The present work is a small portion of a multi-disciplinary science-based study of the physicochemical properties of respirable aerosols containing beryllium. The working hypothesis is that Chronic Beryllium Disease (CBD) is by controlled dissolution of Be particles in the lung. Recent studies have shown correlations between specific Be production processes and the development of Be sensitivity and CBD. in Beryllium Oxide (BeO) production, 9.8% of the workers develop a sensitivity to Be and 4.9% develop CBD. in vitro cellular dose-response relations have been observed for BeO particles.

This study involves a characterization of BeO materials sampled from the air stream around the production process at Brush Wellman Inc. (Elmore, OH) and laboratory-prepared BeO. One purpose of this work is to determine if lab-prepared material is a good surrogate for the process-generated aerosols for cellular dissolution studies. Both materials were size-separated into six fractions using a five-stage cyclone followed by a electrostatic precipitator (ESP).

In the paper, we firstly publish a new method of internal micrographic visualization of semiconductor and IC. The quality and reliability of the semiconductor materials (SM) and the integrated circuits (IC) have always been concerned Having a high resolution, high reliable and nondestructive detection method is the key element for their improvements.

Silicon oxide layers are used to provide the electrical insulation in the multi-structured ICs. The IC device surfaces are often protected by silicon oxide and silicon nitride layers. Therefore, these insulation layers also cover any inhomogeneity and defect located within the IC devices. It is necessary to have an examining method to detect those defects that are under the insulation layers without damaging the samples. However, the conventional scanning electron microscope (SEM) cannot be utilized to image and examine the surfaces that are positioned below the insulation layers.

Novel nondestructive and contactless method has been developed in our laboratory to obtain the internal micrograph that crosses the surface of the semiconductor material and the integrated circuit.

In this paper, we apply a novel contactless method that we study to investigate the physical properties of the semiconductor materials. This method is based upon the measurement of the surface electron beam exciting potential (SEBEP) on the sample surface. Its advantages include: no direct sample contact or connection needed that is unlike the electron beam inducing current (EBIC) method; no potential barrier required from the measurement.

Electron probe irradiation can cause bending of the energy bands, variation of carriers and excitation of surface potential. The excited surface potential generates the SEBEP signal that can be detected by a SEBEP detector. It is necessary to emphasize that the electron beam can charge the surface that is under the oxide layer when it passes through the sample surface oxide layer.

It is known that the diffusion length L and the average lifetime τ of the non-equilibrium carries can be measured by other methods such as the cathodoluminescent method and the contacting method..

It is very important to study a new method of nondestructive internal microtomography of semiconductors and IC. in this paper, we report some research results that were obtained in resent years using nondestructive internal microtomography (NDIMT) to study semiconductor materials(SM) and microelectronic devices (MD) in SEM. Now we can apply this method to detect the microstructures and defects in the subsurface of SM. The conditions of microstructures and the defects being or not in the subsurface of SM used directly depend on the quality of MD. By attaching a special attachment that was devised based on the NDIMT to SEM we can perform nondestructive internal microtomographic visualization of the subsurface of SM the tested SM may be used latter to produce MD. in this way NDIMT may be used to select good quality SM which can then be used for research and production of MD. The product yield and reliabilities of MD can therefore be improved.

The formation of a silicon alloy has been achieved by electron beam irradiation of a nickel-silicon bilayer. This process, called SiDWEL1 , has been developed by Quantiscript. The nickel-silicon bilayer is very thin and the electron beam operates at low energy and current. Silicide formation occurred around the interaction volume of the electrons within the material. This paper describes the nature of the structures produced and the origin of the difficulties encountered with the characterization. The necessity of further analysis with TEM based techniques is highlighted.

Figure 1 presents a cross-section of a typical sample. The growth of silicide grains is induced by the e-beam irradiation of the stack for few microseconds. Nucieation is initiated by the diffusion of silicon atoms in nickel grains, induced by the heating arising from the electron beam interaction with the solid. A new phase is revealed by FE-SEM observation, after wet etching of the nickel film, as shown in figures 2 and 3.

GaN is a semiconductor material with promising applications in display and laser devices. GaNbased thin films have been grown by various methods and intensively investigated. Additionally, GaN nano particles have been prepared by various different methods. in this paper, we report our new finding of the structural modulation of GaN nano crystals induced by electron beam irradiation within a transmission electron microscope (TEM). The origin of the modulation structure is due to the ordering of N vacancies in the GaN nano crystals.

The GaN nano crystals were prepared by d.c arc plasma method. A Philips CM200 TEM with a field emission gun (FEG) operating at 200KV was used in this study. The GaN nano crystals normally show hexagonal shape (see Fig.la). Corresponding electron diffraction pattern along [0001] axis indicates the Wurtzite structure (see Fig. lb). It was unexpected that satellite reflections gradually appeared in the diffraction pattern after the GaN nano crystal had been exposed to the electron beam (see Fig.lc-d).

All scanning electron microscopes, whether they are in laboratory or on the production line, slowly lose performance as the instrument is used. This loss of performance is due to a whole array of contributing factors including misalignments, contamination and increases in source diameter. Identifying a loss in “sharpness” easily recognizes this performance decrease. Reference Material 8091 (RM 8091) is intended primarily for use in routinely checking the sharpness performance of scanning electron microscopes (Fig. 1). RM 8091 is designed to be used in conjunction with the SPECTEL SEM Monitor Program, the NIST Kurtosis program,3 or the University of Tennessee SMART program. RM 8091 is supplied as a small, approximately 2 mm x 2 mm diced semiconductor chip. This sample is capable of being mounted directly on to a wafer, wafer piece or specimen stub for insertion into a laboratory scanning electron microscope or wafer inspection scanning electron microscope.

There are many technical challenges to be overcome before controlled fusion reactions can be achieved. The National Ignition Facility (NIF) at Lawrence Livermore National Laboratory is being developed to initiate fusion reactions using the world's most powerful laser. Essential components of the Facility are the ultra pure silica (SiO2) lenses that focus the powerful laser beams on to the target. Irradiation with a high power laser has been observed to damage the silica lenses, resulting in the formation of defects. The ensuing degradation of the lens performance necessitates its replacement. It is therefore critical to characterize the induced defects and understand the laser damage initiation and evolution, so that damage mitigation strategies can be developed.

Cathodoluminescence (CL) microscopy and spectroscopy enables high spatial resolution and high sensitivity detection of defects in poorly conducting materials. It is therefore an ideal microanalytical technique with which to study laser irradiation-induced defects.

Millions of gallons of high-level radioactive waste are contained in underground tanks at U. S. Department of Energy sites such as Hanford and Savannah River. Most of the radioactivity is due to 137Cs and 90Sr, which must be extracted in order to concentrate the waste. An ion exchanger, crystalline silicotitanate IONSIV® IE911, is being considered for separation of Cs at the Savannah River Site (SRS). While the performance of this ion exchanger has been well characterized under normal operating conditions, Cs removal at slightly elevated temperatures, such as those that may occur in a process upset, is not clear. Our recent study indicates that during exposure to SRS simulant at 55°C and 80°C, an aluminosilicate coating formed on the exchanger surface. There was concern that the coating would affect its ion exchange properties. A LEO 982 field emission scanning electron microscope (FESEM) and an Oxford ISIS energy dispersive x-ray spectrometer (EDS) were used to characterize the coating.

In spite of commercial importance of polyethylene(PE), morphologies of melt crystallized PE have been rarely studied. Although, it was possible to observe polyethylene microstructure, they were based on the observation performed almost exclusively on thin films which were obtained either by casting samples between glass plates, or by microtoming the materials with transmission electron microscope(TEM). Despite the usefulness of TEM for detailed investigation of the polyethylene, it is not suitable for the structure characterization of the bulk samples, for examples, the characterization of a thick testpiece and commercial products of polyethylene itself. For such bulk specimen or thick sample, scanning electron microscope (SEM) is more useful, if the appropriate and reliable sample preparation method is applied.

In this study, we introduce a chemical etching technique for the investigation of melt crystallized polyethylene microstructure by SEM. Especially in this work we studied the characteristic properties and shapes of polyethylene banded spherulite which come from the melt s.

The introduction of organophilic layered silicates into a polyamide matrix significantly improves stiffness and strength [1,2]. Two methods are known to prepare such nanocomposites. For both methods cations such as sodium, potassium, magnesium or calcium, located in the interlayer galleries of the layered silicates must be exchanged by quaternary alkyl ammonium ions containing at least one alkyl chain and so rendering the originally hydrophilic into an organophilic silicate. in the insitu-method monomeric caprolactam is intercalated between the modified silicate interlayers and subsequently polycondensated to polyamide. By this method the silicates can be broken down into their nanoscale building blocks as can be shown by TEM and ESI (Fig. 1). Another more direct possibility to delaminate the silicates is melt mixing in an extruder. with both methods similar degrees of delamination can be achieved.

This paper presents some of our morphological results on polyamide containing organically modified montmorillonite.

Because of its superior cold formability, a great amount of IF steels is being produced by many steel manufacturers. Accordingly, numerous efforts have been made to understand the mechanism of improved plastic strain ratio in Ti-added IF steels1“3. Several mechanisms have been proposed to explain the effect of Ti on the deep drawability of these steels: l)the scavenging effect that is removing carbon and nitrogen from the solution by fixing them as stable precipitates, 2)promotion of (111) texture by fine dispersion of TiC precipitates, and 3)effects of substitutional elements in solid solution4. in spite of these advantages, Ti-added ultra low carbon steels have a disadvantage of high recrystallization temperature. Hayakawa et al.5have reported that recrystallization temperature is sharply rises with the increase in titanium content and reaches a peak when solute titanium is nil, and the acute recrystallization temperature is lowered with the decrease in amount of fine TiC precipitates.

Formation of acicular ferrite grains by dispersing non-metallic inclusions which can act as intragranular nucleation sites within austenite grain is proposed as a method to obtain refined grain structure in steels. The microstructure of acicular ferrite steel consists of fine interlocking ferrite plates nucleated on dispersed non-metallic inclusions. This acicular ferrite structure provides a desirable combination of high strength and good toughness because of its small plate thickness and interlocking microstruture. in Ti-containing low carbon steels, researchers proposed that Ti2O3 or MnS, among inclusions, is the most effective nucleant for intragranular ferrite because of the formation of Mn depleted zone(MDZ) around Ti2O3 or MnS particles. TiN is also reported as a nucleation site owing to the coherency between ferrite and TiN crystals. But It has not been a simple task to identify which inclusions and what mechanisms are really effective in the formation of intragranular acicular ferrite.