Tunable Digital Material Properties of 3D Voxel Printers

Digital materials are composed of many discrete voxels placed in a massively parallel layer deposition process, as opposed to continuous (analog) deposition techniques. We explore the material properties attainable using a voxel-based freeform fabrication process and simulate how the properties can be tuned for a wide range of applications. By varying the precision, geometry, and material of the individual voxels, we obtain continuous control over the density, elastic modulus, CTE, ductility, and failure mode of the material. Also, we demonstrate the effects of several hierarchical voxel “microstructures”, resulting in interesting properties such as negative poisson’s ratio. This implies that digital materials can exhibit widely varying properties in a single desktop fabrication process.Mechanical Engineerin

Method of obtaining intensified image from developed photographic films and plates

A method is explained of obtaining intensified images from silver images on developed photographic films and plates. The steps involve converting silver of the developed film or plate to a radioactive compound by treatment with an aqueous alkaline solution of an organo-S35 compound; placing the treated film or plate in direct contact with a receiver film which is then exposed by radiation from the activated film; and developing and fixing the resulting intensified image on the receiver film

Fine art photography

ThesisFrom 1839 photography has been a visual method of communication and expression. It is the combination of science and art, and for the one to exist or function without the other is impossible. In 1893, William Powell Frith, a genre painter of Victorian England , _stated: "In my opinion photography has not benefitted arts at all". Art critics did not accept photography as readily as artists and often used the word in a negative way. Now photography is well on the way to being reconized as an art form although most people still believe that it could never be taken seriously as such. In South Africa there is no market for fine art photography, because to much emphasis is placed on the commercial aspects of it. Photographers want their work to be recognized as art, but if they do not treat it as such it will never happen. commercial work goes hand in hand with creativity, but for a fine art photograph to succeed all the aspects of commercial photography should be pushed aside. Art photography speakes for itself and is important as a self expressing medium. There are some basic rules and guide lines to remember in fine art photography such as the rules of composition et cetera, but it is up to the photographer whether to use them or not. No limitations should be imposed on creativity, especially in photography. We need all the creativity we can handle so that photography can be recognized as an art form in this country. "It's important that we photographers show our recognition of the New Status Quo by entering our work in the Cape Town Trienna: and other competitions, fully expecting our entries to be juged not as poor relatives to art, partronisingly and condescendingly , but on an equal footing to any other art medium which is as it should be . We must be seen to be worthy of the recognition given to US. II ("Profoto", Oct./Nov., 1990. Page 3.

Pathophysiological aspects of the problem of prolonged hypokinesia

The changes in man's acitivity due to modern life with automation and sedentary activities and man's exploration of space in a state of weightlessness have accentuated the importance of hypokinesia. The pathogenesis of hypokinesia is discussed. Experiments and results made on man and animals are included

Colour importance driven half-toning

Importance driven half-toning (IDH) presents a method for reduced resource rendering of gray scale images. This approach uses an image pyramid to distribute drawing primitives to different areas of the image based on an importance function. The original paper showed how a wide variety of effects can be achieved using a combination of importance functions and drawing primitives. In this paper we show that by storing multiple pyramid representations of the image we can use different geometric primitives in different areas of the image. The application of IDH to colour is then explored. We show that each of the red, green, and blue bands of the image can be used as bases for IDH. We show some images that are obtained in this manner. Finally we introduce a drawing mode based on a teaching drawing style (Esgrafiado with black ink) where a black layer is scratched off a coloured background. The resulting system provides the artist with a large number of parameters with which to render stylized images. We conclude the paper with some examples of our technique being applied to standard images.Eje: ImágenesRed de Universidades con Carreras en Informática (RedUNCI

Vitamin D3 and Neurofibromatosis Type 1

Vitamin D3 (VD3) and its analogs have been shown to inhibit growth of various cell types found in neurofibromas and pigmented lesions of patients with neurofibromatosis type 1 (NF1). Excimer light irradiation at 150–300 mJ/cm2 in combination with VD3 efficiently inhibited growth of cultured fibroblasts, mast cells, Schwann cells, and melanocytes. Long-term whole body irradiation with narrowband ultraviolet B (UVB) in patients with NF1 significantly increased serum levels of VD3, which was accompanied by a brightening of generalized skin hyperpigmentation. Irradiation with either laser or intense pulsed-radio frequency in combination with topical application of VD3 analogs yielded moderate to fair improvement of café-au-lait macules, small pigmented spots, and skin-fold freckling in NF1 patients. Thus, topical or systemic application of VD3 or one of its analogs may provide beneficial effects to treat skin lesions for patients with NF1

Farbe : eine Arbeitsbibliografie

Farbe: Eine Arbeitsbibliografie. Zusammengestellt von Hans J. Wulff. Für Hinweise danke ich Christine Noll Brinckmann und Jason Grant McKahan

A study of the effect of ink tack, printing pressure, and printing speed on toning in the Driographic system

An investigation was made into one of the newer planographic printing plates, specifically 3M\u27s Dry Plate. This plate is part of the system more popularly known as driography. As with many new processes, driography is beset with several problems. These include plate durability, substrate suitability, and toning. This study deals with the problem of toning and a. method for investigating it. In driography, toning is defined as the inking of the non-image background of the plate. Several factors are thought to have an effect on the amount of toning. Factors such as ink tack, ink temperature, room temperature, humidity, speed, and pressure are included. This investigation specifically researched the relationships between toning and ink tack, inking pressure, and printing speed. A parallel study of these relationships was made on both an IGT Printability Tester and on an ATF Chief 15 press. This was done in an attempt to show that the IGT Printability Tester could print driographically but, under the conditions used, it was a poor predictor of toning. Two methods of recording the effects of toning were used. One method was the recording of absolute densities taken in the non-image areas of the test sheets. The other method was the recording of a. ratio of the density of a solid patch to the density- of a tinted patch. It was hoped that the ratio would eliminate some of the extraneous variables that might affect the amount of toning. It was found, however, that the ratio result tended to record not only the pure toning, but also, the effects of some of the extraneous variables. Several statistical methods v/ere used to analyze the data accumulated. To compare one printing method with another and to compare one recording method with another, a correlation analysis was made and a graphical study done. To determine the reliability of the graphical analysis, a spot check was made using a paired comparison technique. An analysis of variance (ANOVA) was made of the data from each printing and recording method to determine the significant factors in the experiment. This experiment showed that ink tack, inking pressure, printing speed, and their interactions all were significant factors in toning. Unfortunately it was impossible to include some other factors in the experiment which are known to have a significant effect on toning. These include such factors as ink temperature, room temperature, and humidity. More work needs to be done in the area of driography, especially in toning. The crucial question is whether this is a plate or an ink problem. As more control is obtained over toning, the use of driography should increase

Machine vision and the OMV

The orbital Maneuvering Vehicle (OMV) is intended to close with orbiting targets for relocation or servicing. It will be controlled via video signals and thruster activation based upon Earth or space station directives. A human operator is squarely in the middle of the control loop for close work. Without directly addressing future, more autonomous versions of a remote servicer, several techniques that will doubtless be important in a future increase of autonomy also have some direct application to the current situation, particularly in the area of image enhancement and predictive analysis. Several techniques are presentet, and some few have been implemented, which support a machine vision capability proposed to be adequate for detection, recognition, and tracking. Once feasibly implemented, they must then be further modified to operate together in real time. This may be achieved by two courses, the use of an array processor and some initial steps toward data reduction. The methodology or adapting to a vector architecture is discussed in preliminary form, and a highly tentative rationale for data reduction at the front end is also discussed. As a by-product, a working implementation of the most advanced graphic display technique, ray-casting, is described

A reconnaissance space sensing investigation of crustal structure for a strip from the eastern Sierra Nevada to the Colorado Plateau

There are no author-identified significant results in this report. Research progress in applications of ERTS-1 MSS imagery in study of Basin-Range tectonics is summarized. Field reconnaissance of ERTS-1 image anomalies has resulted in recognition of previously unreported fault zones and regional structural control of volcanic and plutonic activity. NIMBUS, Apollo 9, X-15, U-2, and SLAR imagery are discussed with specific applications, and methods of image enhancement and analysis employed in the research are summarized. Areas studied and methods employed in geologic field work are outlined