A new approach for three-dimensional(3D)shape measurement based on color-coded fringe and neural networks is *** applying the phase-shift technique to fringe projection,point clouds with high spatial resolution and li...
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A new approach for three-dimensional(3D)shape measurement based on color-coded fringe and neural networks is *** applying the phase-shift technique to fringe projection,point clouds with high spatial resolution and limited accuracy can be ***-pair images obtained from two cameras can be used to compute 3D world coordinates of a point using traditional active triangulation approach in which camera calibration is *** general camera model is often nonlinear and requires good initial estimates to converge to a *** network is a well-known approach to approximate a nonlinear system without an explicit physical model,so in this work it is used to train the stereo vision application system to calculating 3D world coordinates so that the camera calibration can be *** training set for our neural network consists of a variety of stereo-pair images and corresponding 3D world *** the 3D shape measurement system where neural network is used the picture elements correspondence in image is *** the camera's interior and exterior orientation parameters are not estimated by camera calibration,epipolar condition is unable to be *** the general one-dimensional phase-shift technique can not solve the correspondence *** this paper the picture elements correspondence problem is solved by using projected color-coded fringes with different *** the high accurate correspond points are decided,high precision dense 3D points cloud can be calculated by the well trained *** obvious advantage of this approach is that high spatial resolution can be obtained by the phase-shift technique and high accuracy 3D object point coordinates are achieved by the well trained net which is not dependent on the camera model and will work for any type of *** experiments can verify the performance of this method.
Purpose-The purpose of this paper was to study the gel casting of metal powder by agar gelation through Mold DIS process:verifying the feasibility and improving the processing parameters to prepare stable metal slurry...
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Purpose-The purpose of this paper was to study the gel casting of metal powder by agar gelation through Mold DIS process:verifying the feasibility and improving the processing parameters to prepare stable metal slurry and strong green ***/methodology/approach-The optimal processing parameters have been achieved after investigating the effects of this parameters,such as temperature,agar content,dispersant concentration,solid volume loading,*** rheologic behavior of metal slurry and the character of formed green body have also been *** mixture and dispersion mechanism of metal slurry,the consolidation forming and sintering technology of green body have been preliminary studied based on analysis of experimental ***-The results showed that the optimal pH range was 8.5～9.5 while the grain size distribution of 2～30 μm and the suspension with 55% solids,which could be prepared by adding proper dispersant(Polyvinyl Alcohol).The agar and dispersant content had great effect on the properties of slurry:when 1.0wt.% dispersant and 0.7wt.% agar content(referred to dry solid)was adopted,stable metal slurry with viscosity less than 1 pa?s and green body with bending strength of 2.7 MPa was *** sintered bodies with uniform structure,relative density of 90% and yield strength of 150 MPa,have been prepared at 1300℃/30min in *** implications-This process could be applied to rapid prototyping of complex shape metal products,for example rotor ***/value-The paper dealt with experimental works by innovative *** particular,before this paper,the investigation on the character of metal slurry and green body,the determination of processing parameters of gel casing of metal powder by agar gelation were very lacking.
Drip emitters are the key functional parts that realize the water-saving purpose of drip irrigation ***,it is very difficult to develop new types of drip emitters because of their mini-scale(the cross-sectional area r...
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Drip emitters are the key functional parts that realize the water-saving purpose of drip irrigation ***,it is very difficult to develop new types of drip emitters because of their mini-scale(the cross-sectional area ranges from 0.5mm to 1.0mm)and complex inner *** this study,we designed three drip emitters with novel channel forms,and transformed these ideas into real models by use of rapid prototyping and manufacturing(RPM).We focused on the effects of three different materials on emitters' hydraulic performances ***,three new types of emitters with photosensitive resin were manufactured by use of the rapid prototyping method of SLA(Stereolithography Apparatus).Then,the emitters with polyurethane(PU)material similar to ABS plastic were duplicated by using vacuum casting technology,in which the SLA prototype was used as the sample model for making a silicone rubber *** with plastic emitters produced by the steel tool of injection,the discharge of the emitter prototypes fabricated by SLA and vacuum casting methods were measured under nine different pressures that include 50,75,100,125,150,175,200,225,and *** results showed that the discharge of SLA and vacuum casting emitters were about 17.8% and 11.1% smaller than that of plastic emitters respectively,which means that the hydraulic accuracy of SLA emitters can be increased by a factor of using vacuum *** addition,the development cost and cycle were saved by more than 75% without manufacturing steel *** series of hydraulic experiments and structure optimizations,three types of drip emitters,including eddy drip-arrows,pre-depositing drippers and round-flow drip-tapes were developed successfully.
Three-dimensional highly porous structural Poly(DL-lactic-co-glycolic acid)/Tricalcium phosphate(PLGA/TCP)scaffolds(10mm in diameter and 10 in height)were synthesized via a rapid prototyping(RP)*** bone morphogenetic ...
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Three-dimensional highly porous structural Poly(DL-lactic-co-glycolic acid)/Tricalcium phosphate(PLGA/TCP)scaffolds(10mm in diameter and 10 in height)were synthesized via a rapid prototyping(RP)*** bone morphogenetic protein(bBMP)was loaded into the biopolymer scaffolds(PLGA/TCP/bBMP).Both the PLGA/TCP scaffolds and the PLGA/TCP-bBMP composites were observed by scanning electron *** intervertebral body fusion at L2～3 and L4～5 levels were performed on fifteen goats using one of the following graft materials:RP synthesized PLGA/TCP scaffolds(group A,n=10);PLGA/TCP-bBMP composites(group B,n=10);and autogenous iliac bone graft(group C,n=10).The animals in each group were killed twenty-four weeks after surgery and the spine fusion were evaluated by a general observation,a manual palpation test,histological analyses and *** a result,RP established PLGA/TCP scaffolds with good biomaterial properties including satisfactory microstructure and *** was efficiently loaded on the highly porous structral scaffolds to produce a new biomimetic artificial grafting *** group A,histological analyses showed PLGA/TCP scaffolds were biocompatible and ***,no newly formed bone was *** group B,highly cellular bone marrow between the newly formed trabecular bone were present in the fusion *** group C,there was a reduced amount of newly formed ***-four weeks after surgery,the fusion rate of lumbar intervertebral body fusion in group A,B and C was 10%(1/10),80%(8/10)and 50%(5/10),*** fusion rate was significantly higher in group B compared with groups of A and C(P<0.01).Therefore,extracted bovine bone morphogenetic protein can be in vitro efficiently loaded into RP-based highly porous structural PLGA/TCP scaffolds to fabricate a new graft material for spinal ***-based PLGA/TCP/bBMP composites appear to be more effective for intervertebral spinal *** biomimetic artificial graft
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