II. Current developments in the design and production of three- dimensional curved objects - Computational geometry

1971 ◽  
Vol 321 (1545) ◽  
pp. 187-195 ◽  
Keyword(s):  
Computational Geometry ◽  
Three Dimensional ◽  
Computer Hardware ◽  
Mathematical Representation ◽  
Shape Information ◽  
Accurate Representation ◽  
Analysis And Synthesis ◽  
Computer Based ◽  
Curve And Surface Fitting ◽  
Design And Manufacture

The accurate representation of shape which is essential to engineering design and manufacture conventionally has been achieved by two-dimensional drafting but new computer-based methods are being developed. The mathematical representation, manipulation, analysis and synthesis of shape information in a computer is termed computational geometry. A mathematical representation must take into account not only the capabilities and limitations of computer hardware and software but also those of a mathematically unsophisticated user. A distinction is drawn between the fitting of a mathematical representation to a predesigned object and the design of an object ab initio or by modification of an existing mathematical model. Conventional curve and surface fitting techniques have been found to be unsuitable. Several methods of representation which are intended to overcome these problems are discussed.

scholarly journals A computer-based approach for developing linamarase inhibitory agents

2020 ◽  
Vol 5 (7) ◽  
Author(s):  
Lucas Paul ◽  
Celestin N. Mudogo ◽  
Kelvin M. Mtei ◽  
Revocatus L. Machunda ◽  
Fidele Ntie-Kang
Keyword(s):  
Structure Elucidation ◽  
Three Dimensional ◽  
Data Bank ◽  
Competitive Inhibitor ◽  
Industrial Applications ◽  
Dimensional Structure ◽  
Full Understanding ◽  
The Poor ◽  
Computer Based ◽  
Inhibitory Agents

AbstractCassava is a strategic crop, especially for developing countries. However, the presence of cyanogenic compounds in cassava products limits the proper nutrients utilization. Due to the poor availability of structure discovery and elucidation in the Protein Data Bank is limiting the full understanding of the enzyme, how to inhibit it and applications in different fields. There is a need to solve the three-dimensional structure (3-D) of linamarase from cassava. The structural elucidation will allow the development of a competitive inhibitor and various industrial applications of the enzyme. The goal of this review is to summarize and present the available 3-D modeling structure of linamarase enzyme using different computational strategies. This approach could help in determining the structure of linamarase and later guide the structure elucidation in silico and experimentally.

Three Dimensional Detection of the via in the PCB CT Image Using Morphology Operation

2015 ◽  
Vol 752-753 ◽  
pp. 1406-1412
Author(s):  
Lei Zeng ◽  
Jian Chen ◽  
Han Ning Li ◽  
Bin Yan ◽  
Yi Fu Xu ◽  
...  
Keyword(s):  
Nondestructive Testing ◽  
Printed Circuit Board ◽  
Three Dimensional ◽  
Detection Algorithm ◽  
Circuit Board ◽  
Dimensional Structure ◽  
Three Dimension ◽  
Shape Information ◽  
Printed Circuit ◽  
Testing Technology

In modern industry, the nondestructive testing of printed circuit board (PCB) can prevent effectively the system failure and is becoming more and more important. As a vital part of the PCB, the via connects the devices, the components and the wires and plays a very important role for the connection of the circuits. With the development of testing technology, the nondestructive testing of the via extends from two dimension to three dimension in recent years. This paper proposes a three dimensional detection algorithm using morphology method to test the via. The proposed algorithm takes full advantage of the three dimensional structure and shape information of the via. We have used the proposed method to detect via from PCB images with different size and quality, and found the detection performances to be very encouraging.

Application of the Mechanical Impedance of Body Arm Movement Based on the Virtual Tennis System

2013 ◽  
Vol 791-793 ◽  
pp. 1436-1440
Author(s):  
Ling Hang Yang
Keyword(s):  
Virtual Reality ◽  
Three Dimensional ◽  
Arm Movement ◽  
Mechanical Impedance ◽  
Simulation Software ◽  
Computer Hardware ◽  
Calculation Results ◽  
Virtual System ◽  
Dimensional Simulation ◽  
Theoretical Results

With the development of computer hardware and software technology, virtual reality technology of computer has been widely used in various fields. Virtual teaching process is one of the main applications of virtual reality computer technology. Tennis is one of the most common sports. Tennis process mainly includes the process of catching a ball, serving a ball and hitting a ball. Virtual process of tennis system must establish an accurate numerical simulation model to calculate the mechanical impedance during the arm movement of human. According to this, it builds a model of the mechanical impedance of human arm in tennis virtual system using three-dimensional simulation software in this paper and gets the curve of mechanical impedance through the simulation. Finally, the article compares calculation results with the theoretical results and concludes that the theoretical results and simulation results are basically consistent which provide a theoretical reference for the design of the development of virtual system for the human.

Hierarchical Nano/Micro-structured Surfaces with High Surface Area/Volume Ratios

2021 ◽  
pp. 1-36
Author(s):  
Ketki Lichade ◽  
Yizhou Jiang ◽  
Yayue Pan
Keyword(s):  
Surface Structure ◽  
Surface Area ◽  
Light Trapping ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Structure Design ◽  
Surface Structures ◽  
Structured Surfaces ◽  
Design And Manufacture

Abstract Recently, many studies have investigated additive manufacturing of hierarchical surfaces with high surface area/volume (SA/V) ratios, and their performance has been characterized for applications in next-generation functional devices. Despite recent advances, it remains challenging to design and manufacture high SA/V ratio structures with desired functionalities. In this study, we established the complex correlations among the SA/V ratio, surface structure geometry, functionality, and manufacturability in the Two-Photon Polymerization (TPP) process. Inspired by numerous natural structures, we proposed a 3-level hierarchical structure design along with the mathematical modeling of the SA/V ratio. Geometric and manufacturing constraints were modeled to create well-defined three-dimensional hierarchically structured surfaces with a high accuracy. A process flowchart was developed to design the proposed surface structures to achieve the target functionality, SA/V ratio, and geometric accuracy. Surfaces with varied SA/V ratios and hierarchy levels were designed and printed. The wettability and antireflection properties of the fabricated surfaces were characterized. It was observed that the wetting and antireflection properties of the 3-level design could be easily tailored by adjusting the design parameter settings and hierarchy levels. Furthermore, the proposed surface structure could change a naturally-hydrophilic surface to near-superhydrophobic. Geometrical light trapping effects were enabled and the antireflection property could be significantly enhanced (>80% less reflection) by the proposed hierarchical surface structures. Experimental results implied the great potential of the proposed surface structures for various applications such as microfluidics, optics, energy, and interfaces.

Development and Application of Graphics Displays for a Mini-Computer Based Vibration Analysis System

1992 ◽  
Author(s):  
Bill Trevillion
Keyword(s):  
Three Dimensional ◽  
Large Data ◽  
Electric Utility ◽  
Chemical Processing ◽  
Acoustic Data ◽  
Interactive Display ◽  
Computer Based ◽  
Data Files ◽  
Vibration Problems ◽  
Analysis System

Abstract Radian Corporation has developed extensive data display capabilities to analyze vibration and acoustic data from structures and rotating equipment. The Machinery Interactive Display and Analysis System (MIDAS) displays data collected through the acquisition functions of MIDAS. The graphics capabilities include displaying spectra in three-dimensional waterfall and in X-Y formats. Both types of plots can relate vibrations to time, equipment speed, or process parameters. Using menu-driven parameter selection, data can be displayed in formats that are the most useful for analysis. The system runs on a popular mini-computer, and it can be used with a great variety of graphics terminals, workstations, and printer/plotters. The software was designed and written for interactive display and plotting. Automatic plotting of large data files is facilitated by a batch plotting mode. The user can define display formats for the analysis of noise and vibration problems in the electric utility, chemical processing, paper, and automotive industries. This paper describes the history and development of graphics capabilities of the MIDAS system. The system, as illustrated in the examples, has proven efficient and economical for displaying large quantities of data.

scholarly journals Quantitative measurement of syndesmophyte volume and height in ankylosing spondylitis using CT

2013 ◽  
Vol 73 (3) ◽  
pp. 544-550 ◽  
Author(s):  
Sovira Tan ◽  
Jianhua Yao ◽  
John A Flynn ◽  
Lawrence Yao ◽  
Michael M Ward
Keyword(s):  
Ankylosing Spondylitis ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Reliability And Validity ◽  
Intervertebral Disk ◽  
Ct Scans ◽  
Developmental Study ◽  
Coefficients Of Variation ◽  
Spine Ct ◽  
Computer Based

ObjectiveSyndesmophyte growth in ankylosing spondylitis can be difficult to measure using radiographs because of poor visualisation and semiquantitative scoring methods. We developed and tested the reliability and validity of a new computer-based method that fully quantifies syndesmophyte volumes and heights on CT scans.MethodsIn this developmental study, we performed lumbar spine CT scans on 38 patients and used our algorithm to compute syndesmophyte volume and height in four intervertebral disk spaces. To assess reliability, we compared results between two scans performed on the same day in nine patients. To assess validity, we compared computed measures to visual ratings of syndesmophyte volume and height on both CT scans and radiographs by two physician readers.ResultsCoefficients of variation for syndesmophyte volume and height, based on repeat scans, were 2.05% and 2.40%, respectively. Based on Bland–Altman analysis, an increase in syndesmophyte volume of more than 4% or in height of more than 0.20 mm represented a change greater than measurement error. Computed volumes and heights were strongly associated with physician ratings of syndesmophyte volume and height on visual examination of both the CT scans (p<0.0001) and plain radiographs (p<0.002). Syndesmophyte volumes correlated with the Schober test (r=−0.48) and lateral thoracolumbar flexion (r=−0.60).ConclusionsThis new CT-based method that fully quantifies syndesmophytes in three-dimensional space had excellent reliability and face and construct validity. Given its high precision, this method shows promise for longitudinal clinical studies of syndesmophyte development and growth.

The Brain Stem Saccadic Burst Generator Encodes Gaze in Three-Dimensional Space

2008 ◽  
Vol 99 (5) ◽  
pp. 2602-2616 ◽  
Author(s):  
Marion R. Van Horn ◽  
Pierre A. Sylvestre ◽  
Kathleen E. Cullen
Keyword(s):  
Eye Movements ◽  
Brain Stem ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Saccadic Eye Movements ◽  
Three Dimensions ◽  
Related Information ◽  
Computer Based ◽  
Different Depths ◽  
The Brain

When we look between objects located at different depths the horizontal movement of each eye is different from that of the other, yet temporally synchronized. Traditionally, a vergence-specific neuronal subsystem, independent from other oculomotor subsystems, has been thought to generate all eye movements in depth. However, recent studies have challenged this view by unmasking interactions between vergence and saccadic eye movements during disconjugate saccades. Here, we combined experimental and modeling approaches to address whether the premotor command to generate disconjugate saccades originates exclusively in “vergence centers.” We found that the brain stem burst generator, which is commonly assumed to drive only the conjugate component of eye movements, carries substantial vergence-related information during disconjugate saccades. Notably, facilitated vergence velocities during disconjugate saccades were synchronized with the burst onset of excitatory and inhibitory brain stem saccadic burst neurons (SBNs). Furthermore, the time-varying discharge properties of the majority of SBNs (>70%) preferentially encoded the dynamics of an individual eye during disconjugate saccades. When these experimental results were implemented into a computer-based simulation, to further evaluate the contribution of the saccadic burst generator in generating disconjugate saccades, we found that it carries all the vergence drive that is necessary to shape the activity of the abducens motoneurons to which it projects. Taken together, our results provide evidence that the premotor commands from the brain stem saccadic circuitry, to the target motoneurons, are sufficient to ensure the accurate control shifts of gaze in three dimensions.

scholarly journals 3D laser scanning and digital restoration of an archaeological find

2018 ◽  
Vol 178 ◽  
pp. 03013 ◽  
Author(s):  
Stergios Fragkos ◽  
Emanuel Tzimtzimis ◽  
Dimitrios Tzetzis ◽  
Oana Dodun ◽  
Panagiotis Kyratsis
Keyword(s):  
3D Printing ◽  
Laser Scanning ◽  
Three Dimensional ◽  
3D Laser Scanning ◽  
Analytical Methodology ◽  
3D Cad ◽  
Digital Restoration ◽  
Computer Based ◽  
Ancient Ceramic ◽  
Digital Archaeology

The current paper demonstrates the digital recreation and 3D printing of a missing fragment of an ancient ceramic pottery following digitization using a three dimensional laser scanning. The resulting pointcloud of the laser scans was treated with a series of advanced software for the creation of surfaces and ultimately for a digital model. An analytical methodology is presented revealing the step by step approach, which is an innovative way of recreating a missing fragment. Such approach aims to demonstrate the level of contribution that the ever evolving computer based technologies and 3D printing could bring to cultural heritage. The reverse engineering method presented for the reconstruction of a ceramic pottery, which is a part of the larger field of digital archaeology, is believed to benefit a variety of interested parties including 3D CAD users and designers, archaeologists and museum curators.

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