Upward Drawings of Trees on the Minimum Number of Layers

Purpose – Layered manufacturing with curved layers is a recently proposed rapid prototyping (RP) strategy for the manufacture of curved, thin and shell-type parts and the repair of worn surfaces, etc. The present investigation indicates another possible application area. In case of flat-layered RP of computer-aided design models having randomly located, small-dimensioned but critical surface features, adaptive slicing is resorted to. Large number of thin slices have to be employed to preserve the critical features. In contrast, a considerably lower number of curved thin slices would be required to preserve such surface features in case of RP with curved layers. Design/methodology/approach – The method of preservation of critical features by RP with curved layers is formulated and demonstrated for two clusters of critical features on the surface of a part. A minimum number of such curved layers is identified by application of genetic algorithms (GAs) in case of a simple example. GA evolves the shape of the curved layer passing through the lower cluster so as to make a curved layer pass through the upper cluster of critical features. Findings – In the example part, a 21 per cent reduction in the number of layers is achieved by the application of adaptive curved layers over adaptive straight layers. Originality/value – The novelty of the concept is the proposed use of curved layered RP with adaptive slicing for the preservation of critical features in final prototyped part. This methodology, applied to part with two distinct clusters, leads to reduced number of layers compared to that obtained in flat-layered RP.

Download Full-text

Electromagnetic soundings in the sedimentary basin of southern Ontario—A case history

Geophysics ◽

10.1190/1.1441470 ◽

1983 ◽

Vol 48 (3) ◽

pp. 311-330 ◽

Cited By ~ 34

Author(s):

E. Gómez‐Trevino ◽

R. N. Edwards

Keyword(s):

Apparent Resistivity ◽

Sedimentary Basin ◽

Joint Inversion ◽

Earth Model ◽

Electrical Model ◽

Southern Ontario ◽

Number Of Layers ◽

Electromagnetic Soundings ◽

Minimum Number ◽

The Individual

The results of electrical and electromagnetic (EM) soundings conducted in the sedimentary basin of southern Ontario are presented. The sounding sites are located strategically to take advantage of the dipping nature of the sediments, a progressive study being undertaken from shallow to deep sections. The vertical magnetic field transfer function, estimated with a pseudonoise source EM system, and conventional Schlumberger apparent resistivity are jointly inverted. For each site, the layered earth model containing the minimum number of layers is fitted to the data. The joint inversion enables up to eight distinct layers to be identified at some sites. The nonuniquenesses or ambiguities in each model, for example S (conductivity‐thickness product) equivalence of a deep thin conductive layer, are revealed through an eigensolution analysis. The intrinsic ambiguities of the models of the deeper sections are resolved by a systematic, progressive site‐to‐site correlation of electrical units across the basin. For example, the conductivity of a conductive unit is measurable when it is at a shallow depth. In a deeper section, if the unit appears as a thin layer, it is assigned this value of conductivity removing the S‐equivalence ambiguity. The individual inversions combined with the site‐to‐site correlation produce an overall electrical model of the basin consistent with the known geologic section.

Download Full-text

Numerical and Experimental Comparative Analysis of Ballistic Performance of Packages Made of Biaxial and Triaxial Kevlar 29 Fabrics

Autex Research Journal ◽

10.2478/aut-2020-0015 ◽

2020 ◽

Vol 20 (2) ◽

pp. 203-219 ◽

Cited By ~ 1

Author(s):

Justyna Pinkos ◽

Zbigniew Stempien

Keyword(s):

Comparative Analysis ◽

Experimental Research ◽

Ballistic Performance ◽

Residual Velocity ◽

Maximum Deformation ◽

Number Of Layers ◽

Minimum Number ◽

Work Structure ◽

Distribution Of Stress ◽

Ballistic Trauma

AbstractThe objective of this study is a comparative analysis of the ballistic effectiveness of packages made of biaxial and triaxial Kevlar 29 fabrics under the hitting of Parabellum 9×19 bullet. We conduct both numerical simulations using the LS-Dyna program and experimental research in a ballistic research laboratory. Based on the comparative analysis of the results from the numerical and experimental research, demonstrated differences exist in the ballistic effectiveness between the packages made of biaxial fabrics and the packages consisting of triaxial fabrics. For this purpose, the residual velocity of the bullet is analyzed in detail in terms of the maximum deformation cone, the shape of the deformation cone, and the distribution of stress for the textile ballistic packages. It is established that the packages made of triaxial fabric show a considerably smaller deformation cone compared with the packages made of biaxial fabric, a more favorable shape of the deformation cone from the perspective of ballistic trauma and distribution of stress similar to materials with isotropic properties. Poorer properties are recorded for these packages in the case of the minimum number of layers necessary for stopping the bullet, which arises from the open-work structure of the fabric.

Download Full-text

Synthesis of Conveying Machine Satisfying Minimum Number of Layers.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series C ◽

10.1299/kikaic.63.2490 ◽

1997 ◽

Vol 63 (611) ◽

pp. 2490-2495

Author(s):

Yoshihiro SAKAMOTO ◽

Kiyoshi OGAWA

Keyword(s):

Number Of Layers ◽

Minimum Number

Download Full-text

1-D inversion of resistivity and induced polarization data for the least number of layers

Geophysics ◽

10.1190/1.1444272 ◽

1997 ◽

Vol 62 (6) ◽

pp. 1724-1729 ◽

Cited By ~ 22

Author(s):

Francisco J. Esparza ◽

Enrique Gómez‐Treviño

Keyword(s):

Reference Model ◽

A Priori ◽

Induced Polarization ◽

Thin Layers ◽

Groundwater Prospect ◽

Number Of Layers ◽

Data Vector ◽

Resistivity Model ◽

Minimum Number ◽

Electrical Sounding

An automatic inverse method has been developed for generating layered earth models from electrical sounding data. The models have the minimum number of layers required to fit a resistivity sounding curve or a combined resistivity and induced polarization sounding. The ground is modeled using a very large number of thin layers to accommodate arbitrary variations. The properties of the layers are optimized using as a constraint the [Formula: see text] norm of the vertical derivative of the resistivity distribution. The use of linear programming leads to piecewise smooth distributions that simulate traditional models made up of a few uniform layers. The process considers from the simplest model of a uniform half‐space to models of many layers, without fixing a priori the number of discontinuities. The solution is sought by iterating a new linear approximation, similar to the classical process of linearization, except that a reference model is not present in either the data vector or the unknown function. For induced polarization soundings, the problem is linear and the solution is obtained in a single iteration, provided an adequate resistivity model is available. The performance of the method is illustrated using numerical experiments and published deep resistivity data from Australia. The method also is applied to combined resistivity and induced polarization soundings from a local groundwater prospect in México.

Download Full-text

Information capacity and bandwidth limitations in the SEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100152392 ◽

1989 ◽

Vol 47 ◽

pp. 84-85

Author(s):

D. C. Joy ◽

R. D. Bunn

Keyword(s):

Signal To Noise Ratio ◽

Critical Dimension ◽

Information Capacity ◽

Acquisition Time ◽

Signal To Noise ◽

Sem Image ◽

Probe Size ◽

Minimum Number ◽

Noise Ratio ◽

Signal Channel

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :

Download Full-text