Beveled Edges Research Articles

Changes in bracket slot tolerance following recycling of direct-bond metallic orthodontic appliances

Stainless steel direct-bond orthodontic brackets manufactured by three different companies were evaluated for changes in ability to be torqued by a rectangular arch wire after being recycled by three commercially available methods. Through two successive recycles, no clinically significant changes in the fit of the arch wire to engage the bracket were found for any of the three different methods. Greater experimental values of bracket tolerance or fit in degrees for wire twist, compared to theoretical calculations by previous investigators, were attributed to beveled edges found on the rectangular arch wires.

Melody bird instrument

An improved instrument is provided for simulating melodious and harmonious sounds of singing birds, such as tropical varieties and the sounds of nighttime insects and small animals, such as the Puerto Rican "coqui". This instrument includes a construction of a plurality of axially aligned air chambers, each having an opening with beveled edges having a bevel angle of 30° into the interior of the respective air chambers, so that upon movement of the instrument through the air by swinging and rotating, a wide variety of melodious and harmonious sounds are produced resembling those of birds and nighttime insects and animals. The plurality of air chambers may be cylindrical, conical or a combination of cylindrical and conical air chambers, and further each air chamber may be sub-divided into two, three, or four sub-chambers, wherein each sub-chamber also includes one opening having beveled edges with a bevel angle of 30° into the interior of the sub-chamber.

Beveled Sections

This paper describes in detail two microtomy techniques by which sections having beveled edges are cut. One method produces free, unsupported bevels; evidence presented in this paper demonstrates that these thin to approximately 50Å. The second method produces bevels which thin to infinite thinness: these are, however, supported by a full section thickness of epoxy resin. Bright-field and dark-field images of beveled sections are presented. The potential for high resolution electron microscopy in these sections is demonstrated and discussed.

The Interpretation of Impact Fractures in Glassy Polymers

While this study was not exhaustive of the area of impact fractures in glassy polymers, it does demonstrate that there are some significant differences between fractures in polymers and those encountered with glass. Those differences can be summarized as follows: (1) the occurrence of pronounced, highly curved hackle marks, which could in many instances be mistaken for conchoidal marks;(2)the appearance of the beveled edges bordering the cratering on the side opposite origin of force; and (3) a more apparent tendency toward an inverse relationship of muzzle velocity and energy to radial fracture length and degree of curving along crater boundaries. The physical laws applicable to the fracture of glass are identical to those extant in the fracture of glassy polymers; no new forces are at play. All of the differences are capable of being explained in terms of the differences in flexibility and flow between glass and polymers, and the resulting differences in tension development and fracture propagation.

A new form of mirror

The production of m i r r o r s at the Borsk Glass Fac to ry for popular use was (in thousand rubles) 1175 in 1962; 1202 in 1963; 1233 in 1964; 1279 in 1965; 1423 in 1966; and 1473 in 1967. In spite of the annual growth in output of the m i r r o r s , their form and construct ion did not undergo any significant change. Into the construct ion of each m i r r o r went; polished glass on a backing with beveled edges, expensive veneer of a super ior quality, nickel plated metal fittings, decorat ive lacquer difficult to obtain, etc. The assembly of the m i r r o r s compr ised a grea t number of operations ca r r i ed out by workers in various p rocesses . The major i ty of these operations were not suitable for mechanization. Fur thermore , the demand for the m i r ro r s with wooden backing and nickel plated metal fittings was dropping.

THE EPITHELIAL STITCH

<h3>To the Editor.</h3> —The paper entitled "Ligature and Suture Material" by W. S. Halsted which you published in the August issue (Arch Surg87:216, 1963) is one of my favorites. I have long hoped that its contents would be widely publicized, particularly the part dealing with the "Epithelial Stitch," and have referred to the latter in the past (<i>JAMA</i>158:776, July 2, 1955). Although Halsted advocated its use in dogs as a means of avoiding infection, we have successfully employed it in several hundred humans for over 20 years. It is especially useful in the repair of jagged lacerations about the face. No other stitch can restore beveled skin edges as well. A subcuticular layer is not necessary as long as interrupted subcutaneous sutures are employed in sufficient number to overcome tension. Interrupted or continuous epithelial stitches may be preferred depending upon the nature of the wound.

Anthony: A Kansas-Oklahoma Border Site

(1961). Anthony: A Kansas-Oklahoma Border Site. Plains Anthropologist: Vol. 6, No. 12, pp. 112-114.

Structural significance of Tertiary volcanic rocks in southwestern Utah

Most of the silicic volcanic rocks of the Great Basin are ignimbrites rather than lava flows. The more common types were probably formed by nuees ardentes which spread laterally as density currents of very high fluidity, but there are aberrant types that may be in some manner transitional between ignimbrites and lava flows, and the whole problem of mechanism of origin is as yet little understood. Uncertainty on this score is of no concern here; mapping of many of the units indicates that, whatever their origin, they assumed a distribution approaching that of an equal volume of water, filling valleys to a common level and forming sheets of substantially uniform thickness where the relief of the pre-existing surface was low. Some of the individual ignimbrites are many hundreds of feet thick and have an areal extent of as much as 10,000 sq. mi. Because each of these extensive and initially flat sheets was formed everywhere at the same instant of time, they are very nearly ideal stratigraphic units. They occur in most parts of the Great Basin and range in age through most of the Tertiary. Eleven ignimbrites which are widespread in southeastern Utah are described and given formal stratigraphic names. The fact that the oldest of them lies unconformably across the beveled edges of thrusts and folds involving late Cretaceous strata indicates that the beginning of volcanic activity postdates the Laramide orogeny. As planar units which provide a record of Tertiary crustal movements, the ignimbrites confirm the Gilbert theory, based originally on physiographic evidence, that block faulting has been the characteristic type of post-Laramide deformation in the Great Basin. The stratigraphic-structural approach makes it possible 1) to work out the geometry of the block faulting with a precision not obtainable by use of displaced erosion surfaces; 2) to deal with episodes of block faulting that occurred during the early Tertiary and are not expressed by the present topography; and 3) to crossdate these and other geologic events on a regional scale. On the basis of detailed work in southwestern Utah, and reconnaissance elsewhere, it is stated as a deliberately provocative working hypothesis that block faulting has been the only type of regional tectonism in the Great Basin in postorogenic time. The first requirement in testing this hypothesis is the recognition, as such, of flexures and thrust faults developed 1) by emplacement of hypabyssal intrusions, and 2) by gravity sliding from primary relief features raised by intrusion and block faulting. These 2 classes of structures are of much interest in their own right; their significance for present purposes is merely that they may be readily mistaken as evidences of regional tectonism. Equally critical is the need for distinguishing postorogenic deformational effects from those produced during the orogeny. Examples are given of use of the ignimbrites in making these distinctions.

Nonlinear Acoustic Properties of Orifices of Varied Shapes and Edge Conditions

The results of a study of the effect of shape and orifice edge conditions the nonlinear acoustic properties of orifices are presented. The samples studied consisted of orifices of circular, rectangular, and square shape in thin orifice plates. Varied edge conditions considered are square, round, and symmetric and nonsymmetric beveled edges for circular orifices in thick plates. These samples were studied for sinusoidal volume velocity in the orifice. It is found that for all the symmetric samples the pressure contains odd harmonics while for the nonsymmetric sample a steady component and second harmonic component are superimposed on the odd harmonies. An equation for the pressure-flow relation is given which is applicable to both symmetric and nonsymmetric orifices.

Thickness-Shear and Flexural Vibrations of Contoured Crystal Plates

An approximate method is devised for calculating frequencies of thickness-shear and flexural vibrations of crystal plates of varying thickness. Applications are made to plates having the shape of a double wedge and to plates with beveled edges.

Beveled or “Rotary” Points

Campbell and Ellis in their article on the Rio Grande Atrisco Sites (American Antiquity Vol. 17, No. 3, 1952) say: “Perhaps the most interesting characteristic of the type (5 out of 8 specimens) is its tendency to show a definite rifling or beveling which would presumably insure its whirling in flight.” This is an amazing statement to find in a serious report made by two competent modern archaeologists.Beveling the edges of points is a very ancient trait. Fluted points have been found with beveled edges. However the reason for this beveling was not to insure the spinning of the shaft in flight; beveling is not productive of that effect. In fact, aerodynamically, there is not enough force generated against the surface of these bevels on any point small enough to serve as an arrow or atlatl dart tip, to spin the shaft. Spinning is achieved by the set of the feathering, but we know of no use of unfeathered arrows on this continent. Even the early atlatl darts seem to have been feathered at the nock end.

Potter-bucky Table Adapted for Multiple Exposures

THE serialographs and polygraphs on the market, while serving a very useful purpose, are rather bulky and cumbersome. One type requires an additional table or support. Another type, which is heavy, has to be placed upon and removed from the table before and after use. Where space is limited, and there is no room for an additional table, and to overcome the necessity of handling a heavy piece of apparatus, it has seemed to me that it might be worth while to adapt the Potter-Bucky table for making multiple exposures. It was rather surprising to find that, with a few simple items, at a very nominal cost, it was possible to accomplish this. The device was adapted to an Acme-International Potter-Bucky table No.3. With slight modification, I think it can be applied to any combination Potter-Bucky table and trochoscope. The Acme table top has raised beveled edges. Within the depressed portion, which is 20 inches wide, is placed a piece of sheet lead (4 pounds to the square foot) measuring 20 × 25 inches. The exact center of the sheet lead is obtained, and an opening cut therein which measures 5 1/2×42/3 inches. The larger measurement of this opening is crosswise. This opening allows for six exposures on one 11 × 14 film (Fig. 3). In order to avoid scratching the table top with the sheet lead, it is enclosed within a tightly fitting vello cloth (black) envelope. This permits easy movement, does not scratch the table top, and does not raise the patient more than 1/8 to 3/16 of an inch, and is not uncomfortable to rest upon. It is not necessary to remove this from the table while doing routine work, for it is easily displaced to either end of the table. The opening in the lead is easily discerned through the vello cloth. With the level of the upper limit of the opening, a straight line is drawn from the opening across the cloth towards the loading side of the table. A white thread is sewed along this line, to make a permanent mark, and is used as a guide which determines the position of the “indicator,” and, in turn, the position of the tray for the first exposure. Within the Bucky tray (Fig. 4). I have three strips of wood, which permit the entry of an 11 × 14 cassette, and also permit a displacement of 5½ inches crosswise. The three strips of wood are so arranged (U-shape) that half the width of the film corresponds to the opening within the sheet lead on the table. Shifting the cassette crosswise brings the other half of the film under the opening. The Acme table top is equipped with a rod along the entire side, which is ordinarily utilized for attaching a compression band. A shoulder, about one inch wide, which rides over this rod is constructed (Fig. 1). This shoulder has a descending arm fixed at right angles. There is also a wing nut which fixes this shoulder in position along any part of the rod.

A NEW PLASTER KNIFE

This knife is designed to facilitate the cutting down of plaster casts and comprises a handle, shaft, removable standardized blades, and a hand rest for pressure on the blades, an eight pointed revolving wheel on the under surface of the shaft, and a pick at the end of the handle. The accompanying illustration shows the parts of the knife individually and assembled for operation. Two knife blades operate parallel to each other at one end of the knife, with their beveled edges away from each other. They serve to cut a strip of plaster, thus obviating any possibility of jamming of the knife blades, which is a common occurrence with the usual type of plaster knife. The blades are standardized and easily replaced by unscrewing a circular knob, which holds them in position. The change of blades can be accomplished in a few seconds. The knob serves an additional purpose

Relation of the Apex of Solar Motion to Proper Motion and on the Cause of the Differences of its Position From Radial Velocities and Proper Motions

desert lands are accomplished. Neither feature is confined to areas which are situated at the mouths of canyons. Both are displayed in bajada belts where rock-floors are present and where the once even surfaces are worn out on the beveled edges of tilted strata. The Calico range, in the Mojave desert, north of Daggett, California, is a notable but not an isolated example. No eminence of the Great Basin region appears, at first glance, to be more certainly a 'lost mountain,' a lofty range buried up to its shoulders in its own debris. The bajadas on either side of the ridge all but meet over its summit. So low and rounded is the crest that manifestly there is no opportunity for extensive outwash around the borders. There is, in this instance, not only remarkable dissection of the bajada belt taking place at the present time but a widening of the apparent lines of drainage into wide flatbottomed esplanades with deep reentrants. Elsewhere there is the anomaly of a long sinuous terrace several hundreds of feet in height separating the higher general plains-surface from the lower local plains-level. In this we get a glimpse of the formation of those heretofore inexplicable but characteristic desert features known as plateau-plains. In their last stage the isolated T6wa-yal-lane, Acoma and Chupadera mesas, of New Mexico, are conspicuous illustrations. To this phase of the problem attention is later turned. The feature of desert bajada-terracing, when explained upon a strictly aqueous basis, cannot but lead to complete misinterpretation. The phenomenon has no necessary connection with former and greater stream-activity. It is one of the wide-spread characteristics of desert lands. It is far more largely the result of wind-action than of wateraction. Its marvellous aspect is the great rapidity with which it takes form. It is, in reality, one of the subordinate expressions of regional eolation.

An Epitome of the History of Medicine. By Roswell Park, A. M., M. D., Professor of Surgery in the Medicial Department of the University of Buffalo, etc. Illustrated with portraits and other engravings. One volume, royal octavo, pages xiv‐348. Extra cloth, beveled edges, $2.00 net. The F. A. Davis Co., Publishers, 1914 and 1916 Cherry Street, Philadelphia

An Epitome of the History of Medicine. By Roswell Park, A. M., M. D., Professor of Surgery in the Medicial Department of the University of Buffalo, etc. Illustrated with portraits and other engravings. One volume, royal octavo, pages xiv‐348. Extra cloth, beveled edges, $2.00 net. The F. A. Davis Co., Publishers, 1914 and 1916 Cherry Street, Philadelphia