Search

In this paper theoretical and experimental investigations of the moment causing roller skew with account taken of the moment of resistance to motion are presented. It is shown that it is possible to choose the working surface radii in such a way that the roller is self-stabilized without any contact between the roller and the side flange and the moment of resistance to motion is minimized at the same time.

The reaction of fibroblasts to the elastic properties of the substratum was studied using elastic collagen films. These films were stretched in one axis to give a substratum which was anisotropic in its elasticity and deformability. Analysis of the orientation of fibroblasts cultured on these substrata showed that they oriented along the axis of stretch which was also the axis of fibre alignment. This orientation was significantly reduced when the films were made less elastic by attachment to a glass slide and chemical fixation. Neither of these procedures appeared to alter the surface shape of these films, which suggests that the elastic properties of the substratum markedly influence the orientation of fibroblasts. The orientation of locomotion of neutrophil leukocytes on elastic collagen films was also analysed and no bias along the axis of stretch was observed. This was compared with neutrophil locomotion in 3-D stretched collagen gels, in which a strong bias along the axis of stretch and of fibre alignment was observed. The possible reasons for the response of these two cell types is discussed.

The temperature fields in axisymmetric thick-walled shells with different middle surface shape are investigated.

Ion bombardment is an important process in surface analysis, not only for surface cleaning, but also for obtaining composition-depth profiles through thin films and interfaces. Although the use of depth profiling is well established for initially flat surfaces and the problems associated with ion-induced artefacts such as surface topography, preferential sputtering and redeposition are well recognized, the additional problems which occur when non-flat surfaces are bombarded have been neglected. For example, depth profile analysis of rods, wires, fibres, etc., using Auger electron spectroscopy is now of interest for many commercial purposes. However, the erosion of such geometries is non-uniform since different angles of incidence are presented to the incoming ion beam. In this paper, computer simulations are presented which illustrate the erosion of such geometries and a quantitative analysis is given for the resulting degradation in depth resolution as a function of sample and electron beam diameter.

In ternary regular systems, the stability limit surfaces are functions of three binary-interaction parameters. These parameters are used to classify the surface shape and to identify the characteristic lines which exist in a ternary system. When considering the effect of small alloy additions on regular systems, one finds that their effect on stability is related to their effect on structure.

Large local magnetic anomalies observed from measured magnetic properties of pyroxenites of the marginal ultrabasic and basic rocks of the Loch Ailsh alkaline intrusion in the Assynt district of northwest Scotland are not reconcilable with the hypothesis that the intrusion is a stratified laccolith. Rather than a low-angle structure, the intrusion is a steeply dipping sheet at the contact between syenite and limestone country rock. By analogy, similar locally developed anomalies along the southern margin of the Loch Borralan complex are interpreted as due to steeply dipping rocks occupying the same general position between limestone and syenite.

Visualization of chromosomal surface architecture using a new light-microscopical method A new method is described, by which the surface architecture of chromosomes can be visualized using light microscope. The principles of the method include 1. 1. the coating of chromosomes with a thin layer of evaporated gold to increase light reflection; 2. 2. the use of oblique and asymmetrical illumination which creates shadows across the surface of chromosomes such that elevations appear bright and depression dark. The chromosomes thus give a three-dimensional appearance. This method can be used to demonstrate correlations between the Giemsa banding pattern and the surface architecture of chromosomes: each Giemsa positive area clearly corresponds to an elevation of the chromosomal surface.

An equation using only easily determined physical properties of particles has been developed for calculating the slip velocity of nonspherical particulate solids falling in fluid media in the intermediate flow range where neither the Stokes nor Newton law applies. The variation in Reynolds numbers covered by this work ranged from 12 to 460. Slip velocities calculated from the equation differed from experimental data by an average deviation of only 3.7% when solids of a wide range of diameters (156 to 1,247 microns), densities (71 to 475 lb./cu. ft.), surface shape factors (0.40 to 0.97), and gases of a wide density range (0.01 to 0.31 lb./cu. ft.) were utilized. Thirty-eight different gas-solid systems were studied.

The spectrum of the far-field displacement radiation from a conventional fault model has been calculated for comparison with the spectrum calculated from the recent Brune model. The spectrums are generally similar, but some of the details are attributed to different effects in the two models. For example, where the spectrum decays as ω−1 at intermediate frequencies, the effect is attributed to partial stress drop by the Brune theory but to rupture surface shape (width very much less than length) by the conventional theory. Both theories yield an inverse proportionality between the fault dimensions and the corner frequency in the displacement spectrum. The constants of proportionality in the two theories are similar.

A review of the present knowledge of conventional polishing techniques is presented, concentrating particularly on the pitch polishing technique for high precision optical surfaces. This technique still depends completely on the artistry of highly skilled opticians who have a largely intuitive understanding of the process. The aim of this article is to point out that the course of surface shape development during the polishing process can be explained in terms of available technical knowledge and consequently that an improvement of polishing technique, based on this knowledge, is feasible.

The formula for the surface energy σ S = k F 4 /160π is proved to be nearly valid for any self-consistent surface barrier, independently both of the surface shape and of the potential form. 1) On the basis of Friedel theorem and the extended expression N ( k )≃ k 3 V /3π 2 - k 2 S /8π of Weyl-Laue theorem, it is proved that the formula σ S = k F 4 /160π holds not only for the plane surface but also for the surface of any shape, provided the surface potential barrier is infinitely high. 2) As the Friedel sum rule for the plane surface potential, the charge neutrality condition in the interior is obtained as \begin{aligned} \int_{0}^{k_{F}}\eta(k_{x})k_{x}dk_{x}{=}\frac{\pi{k_{F}}^{2}}{8} \end{aligned} in terms of the phase shift η( k x ). Then the formula σ=βσ S for the surface energy is derived, where \begin{aligned} \beta{=}\frac{80}{\pi}\frac{1}{{k_{F}}^{4}}\int_{0}^{k_{F}}\eta(k_{x}){k_{x}}^{3}dk_{x}-5. \end{aligned} By these formulae, we can prove the approximate validity of σ S (or β≃1) for any self-...

A numerical solution capability is developed for the solution of problems in three dimensional elastostatics. The solution method utilizes singular integral equations which can be solved numerically for the unknown surface tractions and displacements for the fully mixed boundary value problem. The method is independent of the surface shape and data specification and has been fully automated. Some sample problems are solved to verify the formulation. In addition the method has been used to investigate a significant problem with stress singularities.

In this paper I classified the reflecting image methods among surface measurements, and described the properties of the reflecting image. The definition of the reflecting image has relations with incident angle (φ), and the distance (Δb) between the test surface and the pattern. These relations depend on the microscopic surface shape, and are explained from the amounts of the specular and diffused reflection light.

There are a variety of stereoscopic after-effects in which exposure to a stimulus with a particular slant or curvature affects the perceived slant or curvature of a subsequently presented stimulus. These after-effects have been explained as a consequence of fatigue (a decrease in responsiveness) among neural mechanisms that are tuned to particular disparities or patterns of disparity. In fact, a given disparity pattern is consistent with numerous slants or curvatures; to determine slant or curvature, the visual system must take the viewing distance into account. We took advantage of this property to examine whether the mechanisms underlying the stereoscopic curvature after-effect are tuned to particular disparity patterns or to some other property such as surface curvature. The results clearly support the second hypothesis. Thus, 3D after-effects appear to be caused by adaptation among mechanisms specifying surface shape rather than among mechanisms signaling the disparity pattern.

The survival rates of infants born prematurely have improved as a result of advances in neonatal care, although there remains an increased risk of subsequent disability. Accurate measurement of the shape and appearance of the very preterm brain at term-equivalent age may guide the development of predictive biomarkers of neurological outcome. We demonstrate in 92 preterm infants (born at an average gestational age of 27.0±2.7weeks) scanned at term equivalent age (scanned at 40.4±1.74weeks) that the cortical sulcation ratio varies spatially over the cortical surface at term equivalent age and correlates significantly with gestational age at birth (r=0.49,p

Made available in DSpace on 2015-08-21T17:54:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-11-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Considerando que em estudos anteriores a rugosidade da superfície (dimensão micrométrica) mostrou um fraco efeito sobre a colonização de macroalgas lóticas, nós investigamos os efeitos de tamanhos diferentes (em dimensões milimétricas, uma escala ligeiramente maior do que as investigações anteriores) sobre a abundância de macroalgas em três riachos expostos a pleno sol no sul do Brasil. Utilizamos placas lisas de vidro estéreis com formas diferentes: P – superficie plana sem fendas; S - superfície sinuosa (profundidade de fendas com 0.159 mm ± 0.03), N - superfície não-unifome (0.498 mm ± 0.09), C – superficie com estruturas convexas (1.190 mm ± 0.12), e três tipos de superfície adicionais com diferentes padrões de heterogeneidade construídas apartir da combinação de peças de vidro: P + S (H1), P + S + N (H2) e P + S + N + C (H3). As placas foram instaladas nos riachos e após 105 dias a cobertura percentual da comunidade de macroalgas foi medida. Não houve diferenças significativas entre os tratamentos. Porém, observamos uma tendência das macroalgas ocorrerem dentro das fendas em todos os tratamentos e, isso sugere que, para macroalgas lóticas, os tamanhos das fendas utilizadas neste estudo ainda não foram suficientes para proporcionar um expressivo crescimento de algas, mesmo no tratamento com fendas maiores. Considering that in previous studies, the surface roughness (micrometric dimension) showed a weak effect on the colonization of stream macroalgae, we investigated the effects of different crevice sizes (milimetric dimension, a scale slightly higher than previous investigations) on the macroalgal abundance in three streams exposed to full sunlight in southern Brazil. We used smooth sterile glass plates with different shapes: P – plane surface without crevices; S – sinuous surface (depth of crevices with 0.159 mm ± 0.03); N – non-unifom surface (0.498 mm ± 0.09); C – surfaces with convex structures (1.190 mm ± 0.12); and three additional surface types with different patterns of heterogeneity with combinations of glass pieces: P + S (H1); P + S + N (H2) and P + S + N + C (H3). The plates were placed into the streams and after 105 days the percent cover of macroalgal community was measured. No significant differences among treatments were recorded. However, we observed a trend of macroalgae occurs within the crevices in all treatments and this suggests that, for stream macroalgae, the crevice sizes used in this study was still not enough to provide an expressive algal growth, even in the treatment with bigger crevices. São Paulo State University; UNESP. Av. Dom Antônio Department of Biological Sciences Laboratory of Aquatic Biology Universidade Federal da Integração Latino-Americana (UNILA) São Paulo State University (UNESP), Av. Dom Antônio Department of Biological Sciences Laboratory of Aquatic Biology FAPESP: 2007/52608-1 FAPESP: 2010/17563-0 CNPq: 302354/2008-5 CAPES: 141754/2007-9

Stereoacuity experiments tested definitions of binocularly disparate spatial positions by perturbing the binocular correspondence of the two half-images. Dichoptic translations perturbed zero-order retinal positions; expansions perturbed first-order horizontal separations; rotations perturbed first-order orientations; and anisotropic expansions deformed first-order two-dimensional (2D) structure. Each transformation perturbed relative positions in the two half-images by more than 100 arcsec, but stereoacuity thresholds remained about 10 arcsec. Binocular disparity involves second-order 2D differential structure of the monocular half-images, specifying local surface shape. Stereoacuity is much better than nonstereo acuity, suggesting that monocular spatial signals are binocularly correlated.

We developed orthogonal least-squares techniques for fitting crystalline lens shapes, and used the bootstrap method to determine uncertainties associated with the estimated vertex radii of curvature and asphericities of five different models. Three existing models were investigated including one that uses two separate conics for the anterior and posterior surfaces, and two whole lens models based on a modulated hyperbolic cosine function and on a generalized conic function. Two new models were proposed including one that uses two interdependent conics and a polynomial based whole lens model. The models were used to describe the in vitro shape for a data set of twenty human lenses with ages 7–82years. The two-conic-surface model (7mm zone diameter) and the interdependent surfaces model had significantly lower merit functions than the other three models for the data set, indicating that most likely they can describe human lens shape over a wide age range better than the other models (although with the two-conic-surfaces model being unable to describe the lens equatorial region). Considerable differences were found between some models regarding estimates of radii of curvature and surface asphericities. The hyperbolic cosine model and the new polynomial based whole lens model had the best precision in determining the radii of curvature and surface asphericities across the five considered models. Most models found significant increase in anterior, but not posterior, radius of curvature with age. Most models found a wide scatter of asphericities, but with the asphericities usually being positive and not significantly related to age. As the interdependent surfaces model had lower merit function than three whole lens models, there is further scope to develop an accurate model of the complete shape of human lenses of all ages. The results highlight the continued difficulty in selecting an appropriate model for the crystalline lens shape.

A kinematic chain guided pneumatic displacement gauge system has been proposed to determine quantitatively the surface shape of medium size paraboloidal reflectors. Linear motion lower kinematic pairs have been synthesized in the form of kinematic linkage chain which generates the parabolic curve of predetermined geometry to be used as reference for observation purposes.

A computer modeling method was used to study various factors such as the etch time, the degree of planarization of the sacrificial layer, the original surface shape of the sacrificial layer, the etch ratio, and the original oxide step shape, that directly affect the topography of an etchback planarized surface.

A new type of aspheric surface calibrator has been developed at the National Research Council of Canada. It employs a nonmechanical contact technique for measuring rotationally symmetrical uncoated concave optical surfaces which depart from a sphere by as much as 0.5 mm with a precision of 0.3 microm. Using two precise air bearings for providing rotations about two mutually perpendicular axes, a focused laser beam is scanned across the surface under test. A fringe counting process measures the difference in sag between the surface shape and some reference sphere. Two surfaces, one spherical and the other ellipsoidal, were measured to illustrate the practicality of such an instrument.

The value of surface topographical measurements in the assessment of curve progression in adolescent idiopathic scoliosis is demonstrated in a group of 51 patients. Cobb angles at the commencement of the study ranged from 10 degrees -55 degrees (mean 34.5 degrees), and the mean follow-up period was greater than 2 years. The surface shape method correctly identified curve evolution in 84% of the patient group. Of these, the eight patients who underwent spinal instrumentation were correctly predicted as candidates for surgery.

Rotationally symmetrical aspheric surfaces of spectacle lenses are constructed as either "zonal aspherics" or "continuous aspherics." Zonal aspherics consist of annular zones surrounding a central zone with each zone being nominally spherical with progressively lower surface power the farther the zone is from the surface vertex. Aspheric surfaces are often specified by the radial drop in surface power from the center to the edge of the lens (e.g., Welsh Four-drop), but for assessment purposes the surface shape must be specified more precisely. The formulas for the description of continuous aspherics can be manipulated into different forms. Mathematical descriptions are given or developed which will enable theoretical assessment of the performances of all lenses with rotationally symmetrical aspheric surfaces.

Imagine a smooth surface patch, bounded by a closed contour which is observed stereoscopically. The interior of the patch presents an interpretation problem because of its lack of matchable features. Shading inside the patch is a potentially rich source of information. Its exploitation is facilitated by the stereoscopically matched contour, which supplies boundary conditions on surface shape. Interpretation of the shape of the patch from shading and the stereo contour, is subject to certain ambiguities. The well known Necker-like inversion ambiguity of the surface, with corresponding reflection of the source, is generally capable of being resolved by the stereo contour. But there are three other forms of ambiguity which can occur. The first relates to source position; it may be determined entirely, or else restricted to a set of positions. The second ambiguity is of the contour strip the contour labelled with depth and surface orientation which, for general source position, can undergo just a single, global inversion. The third is of the surface patch itself, given source and contour strip: it is generally determined, but bistable ambiguity may be induced by the presence of two or more points of maximal intensity.

The techniques of acoustic positioning without the use of resonant cavities have been explored and developed over a number of years and the currently available capabilities are reviewed. The performance and characteristics of these nonresonant acoustic systems are described in regard to containerless processing with emphasis on the low-g environment. This includes manipulation and mixing of liquid drops, super-cooling phenomena, heating to temperatures of 1600°C or higher, rapid cooling solidification, and surface shape control. Some possible applications are measurements of physical properties of substances at high temperatures or of highly reactive specimens, and the formation of unique glasses and alloys of new compositions.

The sputtering performance of the proposed TFCX pumped limiter was analyzed using the REDEP computer code. Erosion, redeposition, surface shape and heat flux changes with time, and plasma contamination issues were examined. A carbon coated limiter was found to give acceptable sputtering performance over the TFCX lifetime if, and only if, acceptable redeposition properties of carbon are obtained.

This presentation deals with theoretical and experimental analysis of holographic fringe patterns. More specifically, double-exposure holograms of a cylinder undergoing internal pressure changes were recorded for a known illumination and observation geometry. The experimental results obtained from holograms were compared with theoretically predicted fringe patterns. The prediction of the fringe patterns was achieved using a theoretical model, based on the fringe vector theory of holographic analysis. This model was developed specially for analysis of the fringe patterns as a function of object surface shape, its loading conditions, as well as illumination and observation geometry. The model was tested, using computer simulation, under a number of different loading conditions and recording/reconstruction geometries. In these computer tests, only one quarter of the cylinder was considered because of the symmetry of the obiect. The computer simulated results show the effect that changes in hologram illumination and observation directions, for a given loading condition, have on the appearance of the fringe patterns. The correlation between the experimentally observed fringe patterns and those predicted theoretically is good.

We have calculated the discrete frequencies of the elastic vibration modes localized in the vicinity of a rectangular ridge fabricated from one material that is bonded to the planar surface of a substrate of a second material. These acoustic surface shape resonances correspond to a displacement field that is polarized parallel to the ridge (i.e., it has shear horizontal polarization). The frequencies of these modes are complex because the range in which they occur overlaps the continuum of frequencies of the bulk and surface modes of the substrate, so that they can radiate energy into the latter. The modes are damped thereby, and this damping depends sensitively on the aspect ratio of the ridge and on the material parameters of the ridge and substrate.

Summarizes the methodology of the high-order boundary element method, using cubic spline interpolants for the source distribution and arbitrary surface shape, in the context of two-dimensional time-harmonic scattering problems. The high accuracy and efficiency attained are indicated. Extensions to three dimensional problems are referenced. The paper presents application and results in a circular cylinder. A square dielectric cylinder problem, with singularities at corners, is discussed.

A method for the three dimensional location of lymph nodes with respect to the skin surface is described. The technique is based on the reconstruction of surface shape using isocentric radiographs taken with metal chains draped on the patient. Registration of the radiographic study to the lymphoscintigraphic study is accomplished automatically by matching the location of four radiopaque and radioisotope markers. This method allows nodes to be located in a beam's eye view with any set up of an isocentric radiotherapy machine. An accurate determination of the depth of lymph nodes is obtained, which is of value in electron beam therapy.

There are many applications for mirrors where the surface shape precision need not be of a very high quality. For example, illumination systems in microscopes and projectors, search lights and opthalmoscopes.

The process of extracting three-dimensional shape information from smooth gradations of reflected light intensity. It has been shown by Horn that if certain assumptions are made concerning the reflectance function and illumination of a surface it is possible to formulate and solve equations relating surface shape to the measured intensities in an image of the surface. See intrinsic images .

Underlying the classic binocularity problems of singleness and three-dimensionality is a theory that the stimulus for binocular vision constitutes two two-dimensional images and metric differences between parts of those images. This characterization of the stimulus is criticized here and in its stead an ecologically-based characterization is presented wherein a binocular transformational invariant is shown to specify absolute (body-scaled) size, shape, and distance. The transformation is characterized as a rotation and its specificity to distance assumes a constant interocular distance and either homogeneously textured or extended surfaces. Four experiments demonstrate perceivers' abilities to detect this information and report (verbally or by reaching) the absolute distances of surfaces in stereograms. A fifth experiment revealed that accurate performance did not depend on oculomotor information. The assumptions of texture extent and distribution and constant interocular distance and their possible violations were discussed. A sixth experiment demonstrated that violations of interocular distance are absorbed by surface shapes. The existence and detection of a binocular rotation dissolves the putative problems of singleness and stereopsis, indicates that the importance of having two frontal eyes is for perception of absolute distance, and reformulates the problems for an algorithmic (physiological) theory of vision.

A parametric description of an elastic surface is used as the basis for a free-form shape design package. The energy functional of shape deformation are used to develop the equations of motion for the surface. The user, interacting with the model during a time simulation of its motion, is capable of guiding the surface into desirable configurations. The dynamic nature of these models cause them to seek shapes with desirable properties which can free the user from having to control every aspect of the surface while achieving design goals. The strong analogy between these models and physical systems allows the user to control the shape in intuitive fashions. This approach gives the user considerable control of the global aspects of the shape while retaining control of small scale local shape.

Khandani S, Assadi M, Nejadsatari T, Mehregan I. 2016. Phenetic analysis of the genera medicagoid Trigonella, Medicago and Melilotus (Fabaceae) on seed coat in Iran. Biodiversitas 17: 162-171. Seed morphological characters of 11 species belonging to the Medicagoid Trigonella group from Iran were studied and compared with six species of Trigonella L. (non medicagoid), one species Medicago L. and Melilotus Mill. (Fabaceae), including general shape, size, color, surface shape and testa ornamentation patterns with Scanning Electron Microscope and Stereomicroscope. Phenetic relationships among the species were studied via important seed morphological data by PCA analysis and UPMGA method. Cluster analysis of seed morphology results showed that some of medicagoid Trigonella species clustered with non medicagoid species but majority of them joined together which is in agreement of some references. In conclusion, seed morphological characters show that most Iranian medicagoid Trigonella species are well separated from the other Trigonella species. Also, some of these characters are important in systematic discriminations of the taxa.

Compensation for the effect of missing tissue, using lead filters, was investigated experimentally on a 60Co unit. Curves of lead filter thickness required to compensate for various tissue deficits at different depths were obtained, and from these estimates were made of the errors in tumour dose when compensating at a depth other than the tumour depth. As a means of minimising these errors, two depths (5 and 10 cm) were deduced as being representative of shallow and deep tumours, and the variation of filter thickness with field size investigated at these depths. The errors produced by changes in both SSD and in the use of equivalent squares for rectangular fields were also estimated and found to be negligible within the ranges examined. A semi-empirical method, using central axis depth dose data, was also developed and the resulting compensation curves compared with those obtained experimentally. The effectiveness of compensation was then checked experimentally for a typical surface shape.

Sound reflection of materials is influenced by many factors, e.g. by material type, density, thickness, porosity, angle of sound incidence, surface shape and excitation frequency of acoustic wave. The aim of the paper is to investigate the surface shape effect of expanded polyvinylchloride material on sound reflection. For this reason polyvinylchloride samples of different surface shapes and perforations were produced on universal and CNC machine tool. The material ability to reflect sound of the investigated polyvinylchloride samples was experimentally measured by means of the transfer function method on Kundt's impedance tube. The material samples were subsequently compared in terms of their sound reflection. It was verified that the highest sound reflection was obtained in case of the smooth surface polyvinylchloride sample.

We present a novel method to relight video sequences for multimedia applications given known surface shape and original illumination. The method preserves fine visual details. It requires single view video frames, approximate 3D shape and known illumination only, making it applicable for multimedia and studio production. The technique is demonstrated for relighting video sequences of faces.

There has long been a strong desire to know the deformation and surface shape of tires rotating at high speeds, both in order to verify finite element modeling analysis results and for the design of tire construction and materials. We used the sampling Moiré method to measure sidewall deformation and surface strain of rotating tires when cornering or braking. This method takes photos simultaneously with two cameras placed at a distance from a tire sidewall with a grid sheet laid over it, allowing precision 3D rendering through analysis of these images. This enables a practical and accurate chronological measurement of deformation and surface strain in tires rotating at high speeds, something that was difficult to do until now. But owing to hardware limitations, this had only previously been done in the static state. By combining the sampling Moiré method with high-speed, high-definition cameras, it is possible to measure the time-based shape and surface strain of tires rotating at high speeds, with practical accuracy. In this paper we have made continuous, time-based measurements of surface strain when a sinusoidal slip angle is applied to the tires and measurements of changes in surface strain when enveloping a cleat.

Theme A an ablating nosetip progresses through its trajectory, its surface shape changes continuously. Among the myriad shapes it may assume, there are certain classes of shapes for which the flowfield is grossly unsteady, that is, the flowfield pulsates with a high frequency. Such shape induced flowfield instabilities may seriously compromise the realization of flight objectives. This paper describes the results of an experimental and analytical effort directed toward improving prediction procedures for identifying instability onset and the magnitude and frequency of the pressure fluctuations. A more complete discussion of this work is given in Ref. 1.

The effect of beam diameter on a surface shape produced by a beam scanning-type ion milling has been studied. An argon ion beam accelerated to 10 keV was electrostatically scanned and the scanning speed was varied as a function of the beam bombarding point. The flatly-formed, wedge-shaped and parabolic surfaces exclusive of the milled-region edges were produced on a Si target surface independently of the beam diameter which varied locally.

This preliminary study has shown that bracing may improve the cosmetic appearance of a scoliotic back although the underlying curve remains unchanged. Thirty-two patients treated with the Boston brace for adolescent idiopathic scoliosis were assessed both roentgenographically and by integrated shape imaging system scanning before and after treatment. The mean follow-up time was 16 months. Surface shape improved in 41% of the patients, whereas roentgenographic improvement occurred in only 9%. Roentgenographic measurements should, therefore, be considered in conjunction with corresponding surface shape measurements in the assessment of brace treatment of scoliosis.

Laboratory data showing the influence of planform geometry on the tidal flushing characteristics of small harbors of simple surface shape. The tide ranges, water depths, and planform areas are typical of those encountered in small-boat marinas in Puget Sound, Washington. Each harbor investigated had a single, asymmetric entrance. Flushing and circulation patterns within such harbors depend strongly upon the characteristics of the angular momentum established within the basin and upon the effective penetration distance into the basin of the stream of ambient water entering the harbor on the flood tide. Experimental results confirm that best gross tidal flushing occurs when rectangular harbors have an aspect ratio L/B near unity, and that rounding interior corners of the basin has little effect on the gross tidal flushing but does improve local exchange. Aspect ratios L/B less than 3 lead to the creation of more than one circulation cell (gyre) within the basin.

The period of vibration and the surface shape for the fundamental and several harmonics for free longitudinal oscillations have been deduced for Lake Wakatipu, New Zealand, from the behavior of a laboratory model similar to the Lake. The chief advantages of the model analysis as opposed to full algebraic treatment are the superior speed and the possibility of assessing the accuracy of the results by minor alterations in the original model.