The Ability to See Solid Form in Early Infancy

Perception ◽  
1982 ◽  
Vol 11 (6) ◽  
pp. 677-684 ◽  
Author(s):  
Michael Cook ◽  
Trevor Hine ◽  
Ann Williamson
Keyword(s):  
Strong Evidence ◽  
Three Dimensional ◽  
Early Infancy ◽  
Habituation Rate ◽  
Orientation Condition ◽  
Initial Fixation ◽  
Solid Objects ◽  
Fixed Orientation ◽  
Solid Form ◽  
Single Orientation

The perception of three-dimensional attributes of solid objects by twelve-week-old infants was studied. In the first experiment the rates of habituation of fixation to a cube in a fixed orientation, to one which changed in orientation between presentations, and to a sequence of photographs of cubes in different orientations were determined. Habituation rate was also determined for a photograph of a cube in a fixed orientation. No difference was found between the initial fixation times for solids and photographs, or between the habituation curves for the solids in fixed and varying orientation. For the photographs habituation was much greater for the fixed orientation than the varying orientation condition. These data were interpreted as providing strong evidence that the infants were responding to the stimuli on the basis of their three-dimensional attributes. In the second experiment the same discriminations were examined by a recovery-from-habituation technique. One group was habituated to a cube in a fixed orientation and tested for recovery of fixation to a new orientation. A second group was habituated to a photograph of a cube in a single orientation and tested for recovery to a photograph of a new orientation. Both groups showed recovery and the recovery was the same for both conditions. These data demonstrated that the subjects were, after all, capable of discriminating between different orientations of a solid cube, and they provided no further evidence that the infants were perceiving three-dimensional attributes of the stimuli.

scholarly journals Acemetacin cocrystals and salts: structure solution from powder X-ray data and form selection of the piperazine salt

IUCrJ ◽  
2014 ◽  
Vol 1 (2) ◽  
pp. 136-150 ◽  
Author(s):  
Palash Sanphui ◽  
Geetha Bolla ◽  
Ashwini Nangia ◽  
Vladimir Chernyshev
Keyword(s):  
Hydrogen Bonds ◽  
Dissolution Rate ◽  
Aqueous Medium ◽  
Acid Amide ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
Reference Drug ◽  
X Ray ◽  
Time Period ◽  
Solid Form

Acemetacin (ACM) is a non-steroidal anti-inflammatory drug (NSAID), which causes reduced gastric damage compared with indomethacin. However, acemetacin has a tendency to form a less soluble hydrate in the aqueous medium. We noted difficulties in the preparation of cocrystals and salts of acemetacin by mechanochemical methods, because this drug tends to form a hydrate during any kind of solution-based processing. With the objective to discover a solid form of acemetacin that is stable in the aqueous medium, binary adducts were prepared by the melt method to avoid hydration. The coformers/salt formers reported are pyridine carboxamides [nicotinamide (NAM), isonicotinamide (INA), and picolinamide (PAM)], caprolactam (CPR),p-aminobenzoic acid (PABA), and piperazine (PPZ). The structures of an ACM–INA cocrystal and a binary adduct ACM–PABA were solved using single-crystal X-ray diffraction. Other ACM cocrystals, ACM–PAM and ACM–CPR, and the piperazine salt ACM–PPZ were solved from high-resolution powder X-ray diffraction data. The ACM–INA cocrystal is sustained by the acid...pyridine heterosynthon and N—H...O catemer hydrogen bonds involving the amide group. The acid...amide heterosynthon is present in the ACM–PAM cocrystal, while ACM–CPR contains carboxamide dimers of caprolactam along with acid–carbonyl (ACM) hydrogen bonds. The cocrystals ACM–INA, ACM–PAM and ACM–CPR are three-dimensional isostructural. The carboxyl...carboxyl synthon in ACM–PABA posed difficulty in assigning the position of the H atom, which may indicate proton disorder. In terms of stability, the salts were found to be relatively stable in pH 7 buffer medium over 24 h, but the cocrystals dissociated to give ACM hydrate during the same time period. The ACM–PPZ salt and ACM–nicotinamide cocrystal dissolve five times faster than the stable hydrate form, whereas the ACM–PABA adduct has 2.5 times faster dissolution rate. The pharmaceutically acceptable piperazine salt of acemetacin exhibits superior stability, faster dissolution rate and is able to overcome the hydration tendency of the reference drug.

Simultaneous Determination of Steady Temperatures and Heat Fluxes on Surfaces of Three Dimensional Objects Using FEM

2001 ◽  
Author(s):  
Brian H. Dennis ◽  
George S. Dulikravich
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Heat Conduction ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Multiply Connected ◽  
Three Dimensional Objects ◽  
Solid Objects ◽  
System Solution

Abstract A finite element method (FEM) formulation is presented for the prediction of unknown steady boundary conditions in heat conduction on multiply connected three-dimensional solid objects. The present FEM formulation is capable of determining temperatures and heat fluxes on the boundaries where such quantities are unknown or inaccessible, provided such quantities are sufficiently over-specified on other boundaries. Details of the discretization, linear system solution techniques, regularization, and sample results for 3-D problems are presented.

Ion acoustic double layers forming behind irradiated solid objects in streaming plasmas

2010 ◽  
Vol 76 (3-4) ◽  
pp. 429-439 ◽  
Author(s):  
W. J. MILOCH ◽  
V. L. REKAA ◽  
H. L. PÉCSELI ◽  
J. TRULSEN
Keyword(s):  
Numerical Simulations ◽  
Uv Light ◽  
Three Dimensional ◽  
Double Layers ◽  
Back Side ◽  
Electron Population ◽  
Von Neumann ◽  
Solid Objects ◽  
Ion Acoustic ◽  
Ion Acoustic Double Layers

AbstractSmall solid metallic objects in relative motion to thermal plasmas are studied by numerical simulations. We analyze supersonic motions, where a distinctive ion wake is formed behind obstacles. At these plasma drift velocities, ions enter the wake predominantly due to deflections by the electric field in the sheath around the obstacle. By irradiating the back side of the object by ultraviolet (UV) light, we can induce also an enhanced photo-electron population there. The resulting charge distribution gives rise to a pronounced local potential and plasma density well behind the object. This potential variation has the form of a three-dimensional ion acoustic double layer, containing also an ion phase space vortex. The analysis is supported also by one-dimensional numerical simulations to illustrate the importance of boundary conditions, Dirichlet and von Neumann conditions in particular.

scholarly journals Using Poisson Disk Sampling to Render Oil Particles at Sea

2020 ◽  
Vol 27 (4) ◽  
pp. 31-46
Author(s):  
Vancuong Do ◽  
Hongxiang Ren
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Fluid Simulation ◽  
Oil Film ◽  
Solid Objects ◽  
Marching Cube Algorithm ◽  
Dimensional Simulation ◽  
Oil Particles

Fluid simulation is one of the most complex tasks in three-dimensional simulation. Specifically, in the case of oil spills at sea, the oil film constantly interacts and is influenced by the environment, thus making its composition and properties change over time. In this paper, we tackle this problem by using both Lehr's spreading model and Hoult's drifting model to build the oil spill physical model. Unlike previous studies that only applied the Poisson disk algorithm to static and solid objects, we applied it in a three-dimensional space to divide the oil film into fluid particles. The track of oil particles under the influence of waves, wind, and currents is rendered by the Unity3D tool with C# programming language, which vividly and realistically simulates the collision of oil particles on the ocean scene with obstacles such as buoys and small islands. The result of this research can be used to predict oil spill direction, thus providing the solution to respond and minimize the damage caused by oil spills at sea. We also discuss some improvements to our model by using the Marching cube algorithm to render the Metaball model.

scholarly journals 3D PRINTING AND 3D BIOPRINTING TO USE FOR MEDICAL APPLICATIONS

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Milan Šljivić ◽  
Dragoljub Mirjanić ◽  
Nataša Šljivić ◽  
Cristiano Fragassa ◽  
Ana Pavlović
Keyword(s):  
3D Printing ◽  
Three Dimensional ◽  
3D Models ◽  
Physical Models ◽  
Layer By Layer ◽  
3D Bioprinting ◽  
Solid Objects ◽  
Modern Methods ◽  
Digital File

The Additive manufacturing 3D printing is a process of creating a three dimensional solid objects or rapid prototyping of 3D models from a digital file, which builds layer by layer. The 3D bioprinting is a form sophisticated of 3D printing technology involving cells and tissues for the production of tissue for regenerative medicine, which is also built layer by layer into the area of human tissue or organ. This paper defines the modern methods and materials of the AM, which are used for the development of physical models and individually adjusted implants for 3D printing for medical purposes. The main classification of 3D printing and 3D bioprinting technologies are also defined by typical materials and a field of application. It is proven that 3D printing and 3D bioprinting techniques have a huge potential and a possibility to revolutionize the field of medicine.

Intelligent critiquing and tutoring of spatial reasoning skills

1996 ◽  
Vol 10 (3) ◽  
pp. 235-249 ◽  
Author(s):  
Ole Jakob Mengshoel ◽  
Sanjeev Chauhan ◽  
Yong Se Kim
Keyword(s):  
Engineering Students ◽  
Spatial Reasoning ◽  
Graph Matching ◽  
Three Dimensional ◽  
Partial Solution ◽  
Instructional Software ◽  
Preliminary Evaluation ◽  
Software System ◽  
Solid Objects ◽  
3D Solid

AbstractThe ability to reason spatially is an important skill required for engineers, particularly in engineering design and construction. One aspect of spatial reasoning is visualizing and constructing three-dimensional (3D) solid objects from two-dimensional (2D) projections. To assist in teaching this to engineering students, an instructional software system is being developed at the University of Illinois. This instructional software system is comprised of the Visual Sweeper and the Visual Teacher. The Visual Sweeper is a geometric framework for solving missing view problems. In missing view problems, students create 3D solid objects from two 2D projections by applying operations inverse to orthographic projection. The Visual Teacher, which is the focus of this article, is an intelligent critiquing and tutoring module that gives feedback to the student regarding partial solutions to missing view problems. The Visual Teacher is comprised of a Recognizer and a Critiquer. The Recognizer identifies which solution solid the student's partial solution is closest to. Based on the solution solid and a student's partial solution, the Criti-quer gives critique and advice to the student. The Recognizer is based on an algorithm for bipartite graph matching, while the Critiquer uses a rule-based approach. This paper describes the Visual Teacher, gives examples of how it can be used, presents preliminary evaluation results, and discusses the system's assumptions and limitations.

Computational Mechanics in Virtual Reality: Cutting and Tumour Interactions in a Boundary Element Simulation of Surgery on the Brain

2006 ◽  
Vol 5-6 ◽  
pp. 55-62
Author(s):  
I.A. Jones ◽  
A.A. Becker ◽  
A.T. Glover ◽  
P. Wang ◽  
S.D. Benford ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Boundary Element ◽  
Force Feedback ◽  
Three Dimensional ◽  
Tactile Feedback ◽  
Solid Objects ◽  
Element Simulation ◽  
Recent Developments ◽  
New Applications ◽  
The Brain

Boundary element (BE) analysis is well known as a tool for assessing the stiffness and strength of engineering components, but, along with finite element (FE) techniques, it is also finding new applications as a means of simulating the behaviour of deformable objects within virtual reality simulations since it exploits precisely the same kind of surface-only definition used for visual rendering of three-dimensional solid objects. This paper briefly reviews existing applications of BE and FE within virtual reality, and describes recent work on the BE-based simulation of aspects of surgical operations on the brain, making use of commercial hand-held force-feedback interfaces (haptic devices) to measure the positions of the virtual surgical tools and provide tactile feedback to the user. The paper presents an overview of the project then concentrates on recent developments, including the incorporation of simulated tumours in the virtual brain.

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