OBJECTIVE To describe the thin-section CT findings of arc-welders' pneumoconiosis. MATERIALS AND METHODS Eighty-five arc-welders with a three to 30 (mean, 15)- year history of exposure underwent thin-section CT scanning. The extent of abnormalities detected was correlated with the severity of dyspnea and pulmonary function tests. For comparison, images of 43 smoking males (mean 25 pack-year) ...

In considering the electron microscopic study of sections of tissue as a practical approach to the study of cell structure, the cytologist is faced with a number of possible decisions with respect to the way in which he will prepare his material. Not the least of these is the problem of how thin the section of tissue should be to serve his purpose. A useful section of a sample must satisfy the ...

Introduction Electron microscopic (EM) tomography is proving useful for examining the organization of protein molecules in large molecular machines at critical neural sites, such as synapses. Methods are still in a state of flux, and many steps exist between a neuron and a molecular model of one of its synapses. Here, we show our approach for doing tomography on synaptic structure , hoping ther...

Ornstein (1956) has recently discussed the maximum useful thickness of a section for electron microscopy, as limited by the energy loss of the beam in traversing it and by the chromatic aberration of the objective lens. For working voltages of 50 to 60 kv. his conclusion is almost identical with that which we initially established experimentally (Cosslett, 1951) and later supported by theoretic...

Porosity is a common phenomenon in fabricated parts, which cause stress concentration and leads to yielding, brittle fraction fatigue of structures makes porosity recognition analyzing very important increase efficiency decrease the defects manufactured parts. Many researches have been done order detecting recognizing pores material by different numerical experimental methods. In this paper, an...

the edges of an image define the image boundary. when the image is noisy, it does not become easy to identify the edges. therefore, a method requests to be developed that can identify edges clearly in a noisy image. many methods have been proposed earlier using filters, transforms and wavelets with ant colony optimization (aco) that detect edges. we here used aco for edge detection of noisy ima...

there have been some experimental tests on hollow curved-steel struts with thin-walled square sections, in order to investigate their general behavior, particularly their capacity for bearing differing loads. one set of square tubes are cold-formed into segments of circular arcs with curvature radii, equal to 4000 mm. different lengths of curved struts are fabricated so as to cover a practical ...

This paper introduces the mechanical behavior of precise straightening thin-walled members systematically. As a result of its cross section characteristics of the thin-walled members, traditional straightening theory does not work well in the straightening process of this kind of metal bar stock. Considering the stress evolvement of section during the straightening process, a model was built to...

The resolution of current micro-CT scanning –a few microns – means that for many rocks, significant porosity cannot be imaged directly in three dimensions. Furthermore, alternative approaches, such as reconstruction through simulating sedimentation and diagenesis, may be problematic for many materials whose depositional and diagenetic history is uncertain or complex. In these cases it is necess...