Synthesis, Mobility, and Multifurcation of Deployable Polyhedral Mechanisms With Radially Reciprocating Motion

2014 ◽  
Vol 136 (9) ◽  
Author(s):  
Guowu Wei ◽  
Yao Chen ◽  
Jian S. Dai
Keyword(s):  
Geometric Constraints ◽  
Reciprocating Motion ◽  
Single Plane ◽  
Plane Symmetric ◽  
Loop Equation ◽  
Dual Plane ◽  
Potential Applications ◽  
Number Synthesis ◽  
First Time ◽  
Geometry And Kinematics

Extending the method coined virtual-center-based (VCB) for synthesizing a group of deployable platonic mechanisms with radially reciprocating motion by implanting dual-plane-symmetric 8-bar linkages into the platonic polyhedron bases, this paper proposes for the first time a more general single-plane-symmetric 8-bar linkage and applies it together with the dual-plane-symmetric 8-bar linkage to the synthesis of a family of one-degree of freedom (DOF) highly overconstrained deployable polyhedral mechanisms (DPMs) with radially reciprocating motion. The two 8-bar linkages are compared, and geometry and kinematics of the single-plane-symmetric 8-bar linkage are investigated providing geometric constraints for synthesizing the DPMs. Based on synthesis of the regular DPMs, synthesis of semiregular and Johnson DPMs is implemented, which is illustrated by the synthesis and construction of a deployable rectangular prismatic mechanism and a truncated icosahedral (C60) mechanism. Geometric parameters and number synthesis of typical semiregular and Johnson DPMs based on the Archimedean polyhedrons, prisms and Johnson polyhedrons are presented. Further, movability of the mechanisms is evaluated using symmetry-extended rule, and mobility of the mechanisms is verified with screw-loop equation method; in addition, degree of overconstraint of the mechanisms is investigated by combining the Euler's formula for polyhedrons and the Grübler–Kutzbach formula for mobility analysis of linkages. Ultimately, singular configurations of the mechanisms are revealed and multifurcation of the DPMs is identified. The paper hence presents an intuitive and efficient approach for synthesizing PDMs that have great potential applications in the fields of architecture, manufacturing, robotics, space exploration, and molecule research.

A Spatial Eight-Bar Linkage and Its Association With the Deployable Platonic Mechanisms

2014 ◽  
Vol 6 (2) ◽  
Author(s):  
Guowu Wei ◽  
Jian S. Dai
Keyword(s):  
Closed Form ◽  
Degrees Of Freedom ◽  
Structure Parameters ◽  
Reciprocating Motion ◽  
Motion Feature ◽  
Plane Symmetric ◽  
Dual Plane ◽  
Straight Line ◽  
First Time ◽  
Geometry And Kinematics

This paper presents for the first time a novel two degrees of freedom (2-DOF) single-looped dual-plane-symmetric spatial eight-bar linkage with exact straight-line motion. Geometry and kinematics of the eight-bar linkage are investigated and closed-form equations are presented revealing the exact straight-line motion feature of the linkage on the condition that two symmetric inputs are given. In order to secure two symmetric inputs, a geared eight-bar linkage is then proposed converting the linkage into a 1-DOF linkage of exact straight-line motion. The direction of the straight-line motion produced by the proposed eight-bar linkage is changeable and is only dependent on the structure parameters of the two pairs of V-shaped R-R dyads of the linkage. Further, the proposed eight-bar linkage is applied to the synthesis and construction of a group of deployable Platonic mechanisms with radially reciprocating motion. The virtual-center-based (VCB) method is presented for the synthesis and prototypes of the deployable Platonic mechanisms are fabricated verifying the mobility and motion of the proposed mechanisms.

Synthesis and Construction of a Family of One-DOF Highly Overconstrained Deployable Polyhedral Mechanisms (DPMs)

2012 ◽  
Author(s):  
Guowu Wei ◽  
Jian Dai
Keyword(s):  
Equation Method ◽  
Reciprocating Motion ◽  
Mobility Analysis ◽  
Plane Symmetric ◽  
Kinematic Chains ◽  
Loop Equation ◽  
Euler’S Formula ◽  
The Family

This paper presents a family of one-DOF highly overconstrained regular and semi-regular deployable polyhedral mechanisms (DPMs) that perform radially reciprocating motion. Based on two fundamental kinematic chains with radially reciprocating motion, i.e. the PRRP chain and a novel plane/semi-plane-symmetric spatial eight-bar linkage, two methods, i.e. the virtual-axis-based (VAB) method and the virtual-centre-based (VCB) method are proposed for the synthesis of the family of regular and semi-regular DPMs. Procedure and principle for synthesizing the mechanisms are presented and selected DPMs are constructed based on the five regular Platonic polyhedrons and the semi-regular Archimedean polyhedrons, Prism polyhedrons and Johnson polyhedrons. Mobility of the mechanisms is then analysed and verified using screw-loop equation method and degree of overconstraint of the mechanisms are investigated by combing the Euler’s formula for polyhedrons and the Grübler-Kutzbach formula for mobility analysis of linkages.

Geometry and Kinematics of a Plane-Symmetric Spatial Eight-Bar Linkage With Exact Straight-Line Motion

2011 ◽  
Author(s):  
Guowu Wei ◽  
Jian S. Dai
Keyword(s):  
Isosceles Triangle ◽  
Plane Symmetric ◽  
Straight Line ◽  
Translation Motion ◽  
Motion Characteristics ◽  
First Time ◽  
The Relationship ◽  
Special Case ◽  
Kinematic Properties ◽  
Geometry And Kinematics

In this paper, a novel plane-symmetric spatial eight-bar linkage with exact straight-line motion is proposed for the first time. Geometry and kinematics of the eight-bar linkage are studied and closed-form equations are presented revealing the exact straight-line motion characteristics of the linkage. It is found in this paper that, for the plane-symmetric eight-bar linkage, the angle α between the base and the straight-line traced by the trajectory of the end-effector point is only dependent on the angle φ of the isosceles triangle vertexes of the linkage but independent of the length of the links and dimension of the vertexes. The relationship between α and φ is studied and a special case that leads to parallel translation motion is revealed. Numerical example is then given to illustrate the kinematic properties of the eight-bar linkage.

Linkages That Transfer Rotations to Radially Reciprocating Motion

2010 ◽  
Author(s):  
Guowu Wei ◽  
Jian S. Dai
Keyword(s):  
Constraint Equation ◽  
Equation Method ◽  
Reciprocating Motion ◽  
Loop Equation ◽  
Revolute Joints ◽  
Kinematic Characteristics ◽  
Overconstrained Linkages ◽  
Geometry And Kinematics

Stemming from study of polyhedral and spheroidal linkages and investigation of reciprocating motion of the PRRP chain, this paper presents four overconstrained linkages that are capable of transferring rotations to radially reciprocating motion. The linkages connected by revolute joints are of symmetrical arrangement and mobility one and are analysed by using the screw-loop equation method. The paper further investigates geometry and kinematics of the linkages and reveals their kinematic characteristics, leading to the constraint equation.

Preparation and Characterization of Chitosan-Casein Phosphopeptides Biocomposite Coatings on the Medical Titanium Alloy

2011 ◽  
Vol 480-481 ◽  
pp. 1065-1069
Author(s):  
Bin Liu ◽  
Lin Wang ◽  
Yin Zhong Bu ◽  
Sheng Rong Yang ◽  
Jin Qing Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Attenuated Total Reflectance ◽  
Ti Alloy ◽  
Force Microscopy ◽  
Implant Materials ◽  
Atomic Force ◽  
Casein Phosphopeptides ◽  
Potential Applications ◽  
First Time

Titanium (Ti) and its alloys have been applied in orthopedics as one of the most popular biomedical metallic implant materials. In this work, to enhance the bioactivity, the surface of Ti alloy pre-modified by silane coupling agent and glutaraldehyde was covalently grafted with chitosan (CS) via biochemical multistep self-assembled method. Then, for the first time, the achieved surface was further immobilized with casein phosphopeptides (CPP), which are one group of bioactive peptides released from caseins in the digestive tract and can facilitate the calcium adsorption and usage, to form CS-CPP biocomposite coatings. The structure and composition of the fabricated coatings were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and atomic force microscopy (AFM). As the experimental results indicated, multi-step assembly was successfully performed, and the CS and CPP were assembled onto the Ti alloy surface orderly. It is anticipated that the Ti alloys modified by CS-CPP biocomposite coatings will find potential applications as implant materials in biomedical fields.

scholarly journals Fabrication and Characterization of Lignin/Dendrimer Electrospun Blended Fiber Mats

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 518
Author(s):  
Somaye Akbari ◽  
Addie Bahi ◽  
Ali Farahani ◽  
Abbas S. Milani ◽  
Frank Ko
Keyword(s):  
Thermal Characteristics ◽  
Dendritic Polymers ◽  
Amino Groups ◽  
Fiber Mats ◽  
Potential Applications ◽  
Solution Electrospinning ◽  
Nanofiber Mats ◽  
Softwood Kraft Lignin ◽  
First Time

Blending lignin as the second most abundant polymer in Nature with nanostructured compounds such as dendritic polymers can not only add value to lignin, but also increase its application in various fields. In this study, softwood Kraft lignin/polyamidoamine dendritic polymer (PAMAM) blends were fabricated by the solution electrospinning to produce bead-free nanofiber mats for the first time. The mats were characterized through scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, zeta potential, and thermogravimetry analyses. The chemical intermolecular interactions between the lignin functional groups and abundant amino groups in the PAMAM were verified by FTIR and viscosity measurements. These interactions proved to enhance the mechanical and thermal characteristics of the lignin/PAMAM mats, suggesting their potential applications e.g. in membranes, filtration, controlled release drug delivery, among others.

Topotactic route to synthesis of novel hydroxylated phases: I. Trioctahedral Micas

Clay Minerals ◽  
1986 ◽  
Vol 21 (2) ◽  
pp. 125-131 ◽  
Author(s):  
S. Komarneni ◽  
R. Roy
Keyword(s):  
Ion Exchange ◽  
Alkaline Earth ◽  
Water Molecules ◽  
Hydration Energy ◽  
Hydrothermal Conditions ◽  
Potential Applications ◽  
Clay Layers ◽  
First Time ◽  
Hydrolysis Of ◽  
Alkaline Earth Cations

AbstractK-depleted phlogopite mica was used as a topotactic precursor and treated with alkali (Li+, K+, , Rb+, Cs+), alkaline-earth (Mg2+, Ca2+, Sr2+, Ba2+) and trivalent (Al3+) cations under hydrothermal conditions of 200°C and 30 MPa pressure. K-, NH4-, Rb- and Cs-aluminosilicate micas were synthesised at 200°C in one day. The synthesis of Cs-aluminosilicate mica, with potential applications in the management of nuclear wastes, has been achieved for the first time by this approach. Ion exchange by Li+, Na+ and alkaline-earth cations under hydrothermal conditions did not produce anhydrous mica phases but resulted in hydrous phases with one or two layers of water molecules between the clay layers. The formation of hydrous phases may be attributed to the high hydration energy of the above cations compared to K+, , RB+ and Cs+. Ion exchange with Al3+ produced a chlorite-like phase because of the hydrolysis of Al3+ under these hydrothermal conditions. These studies are of relevance in the immobilization of wastes where hazardous ions can be fixed in highly stable insoluble phases like mica or chlorite.

scholarly journals MOF Decomposition and Introduction of Repairable Defects Using a Photodegradable Strut

2018 ◽  
Author(s):  
Jingjing Yan ◽  
John MacDonald ◽  
Shawn Burdette
Keyword(s):  
Drug Delivery ◽  
Porous Materials ◽  
New Method ◽  
Innovative Approach ◽  
Partial Decomposition ◽  
Multiple Defects ◽  
Potential Applications ◽  
Defect Repair ◽  
First Time ◽  
Interesting Area

Utilizing a photolabile ligand as MOF strut can make a framework undergo full or partial decomposition upon irradiation. For the first time, a nitrophenylacetate derivative has been incorporated into MOF as a backbone linker via PLSE method. The photo-induced decarboxylation of the NPDAC-MOF represents a novel way of degrading a MOF, which provides an innovative approach to formulating photoresponsive porous materials with potential applications in molecular release and drug delivery. When photoactive linker is mixed with non-photolabile linker via partial PLSE, the MOF structure can be retained after irradiation, but with the introduction of multiple defects, offering a new method to create vacancies in MOFs. Defect repair can be achieved by treatment with replacement ligands, the scope of which is an interesting area for developing customizable MOF contents.<br>

scholarly journals Evaluation of anthocyanin encapsulation efficiency into yeast cell by plasmolysis, ethanol, and ultrasound treatments using alone or in combination

Food Research ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 557-562
Author(s):  
M.D. Lieu ◽  
T.T.H. Hoang ◽  
H.N.T. Nguyen ◽  
T.K.T. Dang
Keyword(s):  
Yeast Cell ◽  
Encapsulation Efficiency ◽  
Color Stability ◽  
Water Soluble ◽  
Impact Factors ◽  
Time Treatment ◽  
Treated Sample ◽  
Potential Applications ◽  
The Individual ◽  
First Time

Anthocyanin is a water-soluble color compound of the flavonoid which was successfully encapsulation in Saccharomyces cerevisiae by plasmolysis, ethanol, and ultrasound treatments using alone or in combination in the first time. Treatment agents significantly enhanced the encapsulation efficiency of anthocyanin fluid. The encapsulation yield (EY) of the combined factors was higher than the individual impact factors. Ethanol 10% (v/v) and ultrasound 180 seconds for the highest EY 40.22±0.67%, then ethanol 10% (v/v) and NaCl 10% (w/v) for EY 36.45±0.35%, NaCl 10% and ultrasound for EY 32.14±0.98% lowest. The color stability evaluation of the capsules was carried out at 80°C for 30 minutes. The color lost rate was determined by the spectrometer. The color loss of samples with the un-treatment yeast was 20.45±1.21%, higher than the treated sample. This suggests that anthocyanin encapsulation by yeast cell is efficient in overcoming the effects of high temperatures and having potential applications in food processing.

scholarly journals Validation and characterization of a DNA methylation alcohol biomarker across the life course

2019 ◽  
Author(s):  
Paul Darius Yousefi ◽  
Rebecca Richmond ◽  
Ryan Langdon ◽  
Andrew Ness ◽  
Chunyu Liu ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Parents And Children ◽  
Average Alcohol ◽  
Alcohol Biomarker ◽  
Audit Score ◽  
Potential Applications ◽  
The Life Course ◽  
Offspring Generation ◽  
First Time

AbstractRecently, an alcohol predictor was developed using DNA methylation at 144 CpG sites (DNAm-Alc) as a biomarker for improved clinical or epidemiologic assessment of alcohol-related ill health. We validate the performance and characterize the drivers of this DNAm-Alc for the first time in independent populations. In N=1,049 parents from the Avon Longitudinal Study of Parents and Children (ALSPAC) Accessible Resource for Integrated Epigenomic Studies (ARIES) at midlife, we found DNAm-Alc explained 7.6% of the variation in alcohol intake, roughly half of what had been reported previously, and interestingly explained a larger 9.8% of AUDIT score, a scale of alcohol use disorder. Explanatory capacity in participants from the offspring generation of ARIES measured during adolescence was much lower. However, DNAm-Alc explained 14.3% of the variation in replication using the Head and Neck 5000 (HN5000) clinical cohort that had higher average alcohol consumption. To investigate whether this relationship was being driven by genetic and/or earlier environment confounding we examined how earlier vs. concurrent DNAm-Alc measures predicted AUDIT scores. In both ARIES parental and offspring generations, we observed associations between AUDIT and concurrent, but not earlier DNAm-Alc, suggesting independence from genetic and stable environmental contributions. The stronger relationship between DNAm-Alcs and AUDIT in parents at midlife compared to adolescents despite similar levels of consumption suggests that DNAm-Alc likely reflects long-term patterns of alcohol abuse. Such biomarkers may have potential applications for biomonitoring and risk prediction, especially in cases where reporting bias is a concern.

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