A 3-R(SRS)RP Multi-Loop Mechanism for Space Manipulation: Design, Kinematics, Singularity, and Workspace

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Chuanyang Li ◽  
Hongwei Guo ◽  
Dewei Tang ◽  
Huiyin Yan ◽  
Rongqiang Liu ◽  
...  
Keyword(s):  
Numerical Solutions ◽  
The Novel ◽  
Forward Displacement ◽  
Aerospace Applications ◽  
Wide Range ◽  
Variable Section ◽  
Varying Λ ◽  
Mapping Diagram ◽  
The Given ◽  
Novel Design

Abstract Space manipulation has great prospects in aerospace applications. In this work, a multiloop robot, namely 3-R(SRS)RP multiloop mechanism, is presented. Its design, kinematics, singularity, and workspace are studied. The novel design is mainly reflected in the robot’s structure, variable section, and novel compound hinge. Given these features, the forward-displacement undertaken with a closed-loop method leads to a complex mapping diagram. Only numerical solutions are obtained in this model due to the variable section parameter λ. This variable affects kinematic performances such as bending and folding properties. Moreover, the node differential kinematics and the Jacobian matrix are solved to analyze singular configurations of the mechanism. The workspace is then evaluated via a numerical method with varying λ. The bending and folding properties and the continuous workspace of the given robot vary while changing λ. Hence, the robot has great potentials of good performances in various applications. With this robot, a multimodule manipulator with a wide range of operations, increased mobility and rigidity, variable geometry, and adaptable shape based on mission requirements can be constructed.

scholarly journals A Neuro-Evolution Heuristic Using Active-Set Techniques to Solve a Novel Nonlinear Singular Prediction Differential Model

2022 ◽  
Vol 6 (1) ◽  
pp. 29
Author(s):  
Zulqurnain Sabir ◽  
Muhammad Asif Zahoor Raja ◽  
Thongchai Botmart ◽  
Wajaree Weera
Keyword(s):  
Numerical Solutions ◽  
Mean Squared Error ◽  
Merit Function ◽  
The Novel ◽  
Active Set ◽  
Shape Factors ◽  
Differential Model ◽  
Squared Error ◽  
Global And Local ◽  
Novel Design

In this study, a novel design of a second kind of nonlinear Lane–Emden prediction differential singular model (NLE-PDSM) is presented. The numerical solutions of this model were investigated via a neuro-evolution computing intelligent solver using artificial neural networks (ANNs) optimized by global and local search genetic algorithms (GAs) and the active-set method (ASM), i.e., ANN-GAASM. The novel NLE-PDSM was derived from the standard LE and the PDSM along with the details of singular points, prediction terms and shape factors. The modeling strength of ANN was implemented to create a merit function based on the second kind of NLE-PDSM using the mean squared error, and optimization was performed through the GAASM. The corroboration, validation and excellence of the ANN-GAASM for three distinct problems were established through relative studies from exact solutions on the basis of stability, convergence and robustness. Furthermore, explanations through statistical investigations confirmed the worth of the proposed scheme.

Novel Design of a Three-Dimensional Printed Umbilical Cord Clamp: A Proof of Concept Study

2019 ◽  
Vol 13 (3) ◽  
Author(s):  
Betul Mammadov ◽  
Gulsen Vural ◽  
Ersin Aytac ◽  
Emil Mammadov
Keyword(s):  
Umbilical Cord ◽  
Umbilical Vein ◽  
Human Subjects ◽  
Three Dimensional ◽  
The Novel ◽  
3D Print ◽  
Wide Range ◽  
Fluid Leak ◽  
Umbilical Cords ◽  
Novel Design

Parents frequently report complaints regarding the excessive size of the clamp that create concerns of hooking to the clothes and inducing premature separation of the dried cord. We aimed to design three-dimensional (3D) print and test a novel umbilical clamp which would be smaller, more ergonomic, and would look more appealing to the parents. After the design and 3D printing process, the clamps were tested for fluid leak on fresh umbilical cord specimens. The umbilical vein was cannulated with a 4F feeding tube which was attached to the saline infusion bag inserted in a pressure infusion cuff. The compressed cord width was measured, and the cuff was inflated to 100 mmHg and 200 mmHg. Umbilical cord specimens of 152 patients were included in the main study. The mean umbilical cord diameter (UCD) was 11.1 ± 3.5 mm (range: 4.5–23.3 mm). The compressed cord width mean value after clamping with the novel design clamp was 17.3 ± 2.3 mm compared to the 23.5 ± 3.5 mm with the conventional clamp and this difference was statistically significant (p < 0.001). All of the novel clamps safely and efficiently clamped the umbilical cords without any fluid leak. The novel design umbilical cord clamp is a safe and efficient tool being able to clamp a wide range of umbilical cords. However, a prospective randomized trial on human subjects, safety-efficacy tests by independent healthcare providers, and patient satisfaction surveys are mandatory for the further approval of our claims.

TEM study of boron additions to cobalt aluminide

1988 ◽  
Vol 46 ◽  
pp. 546-547
Author(s):  
Gerald B. Feldewerth
Keyword(s):  
High Temperature ◽  
Turbine Engines ◽  
Major Drawback ◽  
University Of Missouri ◽  
Specific Strength ◽  
Aerospace Applications ◽  
Wide Range ◽  
Ordered Alloys ◽  
The University ◽  
Very High

In recent years an increasing emphasis has been placed on the study of high temperature intermetallic compounds for possible aerospace applications. One group of interest is the B2 aiuminides. This group of intermetaliics has a very high melting temperature, good high temperature, and excellent specific strength. These qualities make it a candidate for applications such as turbine engines. The B2 aiuminides exist over a wide range of compositions and also have a large solubility for third element substitutional additions, which may allow alloying additions to overcome their major drawback, their brittle nature.One B2 aluminide currently being studied is cobalt aluminide. Optical microscopy of CoAl alloys produced at the University of Missouri-Rolla showed a dramatic decrease in the grain size which affects the yield strength and flow stress of long range ordered alloys, and a change in the grain shape with the addition of 0.5 % boron.

Reading Beyond the Code

2018 ◽  
Keyword(s):  
Relevance Theory ◽  
Literary Studies ◽  
The Novel ◽  
Human Communication ◽  
Communicative Acts ◽  
Face To Face ◽  
Code Model ◽  
Wide Range ◽  
Central Claim

This book explores the value for literary studies of relevance theory, an inferential approach to communication in which the expression and recognition of intentions plays a major role. Drawing on a wide range of examples from lyric poetry and the novel, nine of the ten chapters are written by literary specialists and use relevance theory both as an overall framework and as a resource for detailed analysis. The final chapter, written by the co-founder of relevance theory, reviews the issues addressed by the volume and explores their implications for cognitive theories of how communicative acts are interpreted in context. Originally designed to explain how people understand each other in everyday face-to-face exchanges, relevance theory—described in an early review by a literary scholar as ‘the makings of a radically new theory of communication, the first since Aristotle’s’—sheds light on the whole spectrum of human modes of communication, including literature in the broadest sense. Reading Beyond the Code is unique in using relevance theory as a prime resource for literary study, and is also the first to apply the model to a range of phenomena widely seen as supporting an ‘embodied’ conception of cognition and language where sensorimotor processes play a key role. This broadened perspective serves to enhance the value for literary studies of the central claim of relevance theory: that the ‘code model’ is fundamentally inadequate to account for human communication, and in particular for the modes of communication that are proper to literature.

scholarly journals Novel Protein-Repellent and Antibacterial Resins and Cements to Inhibit Lesions and Protect Teeth

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Li Cao ◽  
Junling Wu ◽  
Qiang Zhang ◽  
Bashayer Baras ◽  
Ghalia Bhadila ◽  
...  
Keyword(s):  
Orthodontic Treatment ◽  
The Novel ◽  
Dental Resin ◽  
Biofilm Growth ◽  
New Class ◽  
Dental Resins ◽  
Wide Range ◽  
Oral Biofilms ◽  
One Year

Orthodontic treatment is increasingly popular as people worldwide seek esthetics and better quality of life. In orthodontic treatment, complex appliances and retainers are placed in the patients’ mouths for at least one year, which often lead to biofilm plaque accumulation. This in turn increases the caries-inducing bacteria, decreases the pH of the retained plaque on an enamel surface, and causes white spot lesions (WSLs) in enamel. This article reviews the cutting-edge research on a new class of bioactive and therapeutic dental resins, cements, and adhesives that can inhibit biofilms and protect tooth structures. The novel approaches include the use of protein-repellent and anticaries polymeric dental cements containing 2-methacryloyloxyethyl phosphorylcholine (MPC) and dimethylaminododecyl methacrylate (DMAHDM); multifunctional resins that can inhibit enamel demineralization; protein-repellent and self-etching adhesives to greatly reduce oral biofilm growth; and novel polymethyl methacrylate resins to suppress oral biofilms and acid production. These new materials could reduce biofilm attachment, raise local biofilm pH, and facilitate the remineralization to protect the teeth. This novel class of dental resin with dual benefits of antibacterial and protein-repellent capabilities has the potential for a wide range of dental and biomedical applications to inhibit bacterial infection and protect the tissues.

scholarly journals Optimising the AR Engraved Structure on Light-Guide Facets for a Wide Range of Wavelengths

Optics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 25-42
Author(s):  
Ioseph Gurwich ◽  
Yakov Greenberg ◽  
Kobi Harush ◽  
Yarden Tzabari
Keyword(s):  
Theoretical Analysis ◽  
Light Guide ◽  
Spectral Band ◽  
Angular Range ◽  
The Past ◽  
Input And Output ◽  
Wide Range ◽  
The Given ◽  
Theoretical Results ◽  
Shape And Size

The present study is aimed at designing anti-reflective (AR) engraving on the input–output surfaces of a rectangular light-guide. We estimate AR efficiency, by the transmittance level in the angular range, determined by the light-guide. Using nano-engraving, we achieve a uniform high transmission over a wide range of wavelengths. In the past, we used smoothed conical pins or indentations on the faces of light-guide crystal as the engraved structure. Here, we widen the class of pins under consideration, following the physical model developed in the previous paper. We analyze the smoothed pyramidal pins with different base shapes. The possible effect of randomization of the pins parameters is also examined. The results obtained demonstrate optimized engraved structure with parameters depending on the required spectral range and facet format. The predicted level of transmittance is close to 99%, and its flatness (estimated by the standard deviation) in the required wavelengths range is 0.2%. The theoretical analysis and numerical calculations indicate that the obtained results demonstrate the best transmission (reflection) we can expect for a facet with the given shape and size for the required spectral band. The approach is equally useful for any other form and of the facet. We also discuss a simple way of comparing experimental and theoretical results for a light-guide with the designed input and output features. In this study, as well as in our previous work, we restrict ourselves to rectangular facets. We also consider the limitations on maximal transmission produced by the size and shape of the light-guide facets. The theoretical analysis is performed for an infinite structure and serves as an upper bound on the transmittance for smaller-size apertures.

Study of Temperature Effect on Servovalve-Controlled Fuel Metering Unit

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Bin Wang ◽  
Haocen Zhao ◽  
Ling Yu ◽  
Zhifeng Ye
Keyword(s):  
Steady State ◽  
Temperature Variation ◽  
Dynamic Characteristics ◽  
Numerical Study ◽  
Step Response ◽  
Fuel Temperature ◽  
Wide Range ◽  
Fuel Rate ◽  
Testing Condition ◽  
The Given

It is usual that fuel system of an aero-engine operates within a wide range of temperatures. As a result, this can have effect on both the characteristics and precision of fuel metering unit (FMU), even on the performance and safety of the whole engine. This paper provides theoretical analysis of the effect that fluctuation of fuel temperature has on the controllability of FMU and clarifies the drawbacks of the pure mathematical models considering fuel temperature variation for FMU. Taking the electrohydraulic servovalve-controlled FMU as the numerical study, simulation in AMESim is carried out by thermal hydraulic model under the temperatures ranged from −10 to 60 °C to confirm the effectiveness and precision of the model on the basis of steady-state and dynamic characteristics of FMU. Meanwhile, the FMU testing workbench with temperature adjustment device employing the fuel cooler and heater is established to conduct an experiment of the fuel temperature characteristics. Results show that the experiment matches well with the simulation with a relative error no more than 5% and that 0–50 °C fuel temperature variation produces up to 5.2% decrease in fuel rate. In addition, step response increases with the fuel temperature. Fuel temperature has no virtual impact on the steady-state and dynamic characteristics of FMU under the testing condition in this paper, implying that FMU can operate normally in the given temperature range.

Calculation and Measurement of the Stiffness and Damping Coefficients for a Low Impedance Hydrodynamic Bearing

1997 ◽  
Vol 119 (1) ◽  
pp. 57-63 ◽  
Author(s):  
M. J. Goodwin ◽  
P. J. Ogrodnik ◽  
M. P. Roach ◽  
Y. Fang
Keyword(s):  
Experimental Data ◽  
Dynamic Stiffness ◽  
Perturbation Technique ◽  
The Novel ◽  
Oil Film ◽  
Hydrodynamic Bearing ◽  
Damping Coefficients ◽  
Stiffness And Damping ◽  
Film Stiffness ◽  
Novel Design

This paper describes a combined theoretical and experimental investigation of the eight oil film stiffness and damping coefficients for a novel low impedance hydrodynamic bearing. The novel design incorporates a recess in the bearing surface which is connected to a standard commercial gas bag accumulator; this arrangement reduces the oil film dynamic stiffness and leads to improved machine response and stability. A finite difference method was used to solve Reynolds equation and yield the pressure distribution in the bearing oil film. Integration of the pressure profile then enabled the fluid film forces to be evaluated. A perturbation technique was used to determine the dynamic pressure components, and hence to determine the eight oil film stiffness and damping coefficients. Experimental data was obtained from a laboratory test rig in which a test bearing, floating on a rotating shaft, was excited by a multi-frequency force signal. Measurements of the resulting relative movement between bearing and journal enabled the oil film coefficients to be measured. The results of the work show good agreement between theoretical and experimental data, and indicate that the oil film impedance of the novel design is considerably lower than that of a conventional bearing.

Stranger Fictions

2021 ◽  
Author(s):  
Rebecca C. Johnson
Keyword(s):  
World Literature ◽  
Arab World ◽  
Central Place ◽  
Arabic Literature ◽  
The Novel ◽  
Reading Practices ◽  
Global Circulation ◽  
Wide Range ◽  
History Of ◽  
Modern Arabic

Zaynab, first published in 1913, is widely cited as the first Arabic novel, yet the previous eight decades saw hundreds of novels translated into Arabic from English and French. This vast literary corpus influenced generations of Arab writers but has, until now, been considered a curious footnote in the genre's history. Incorporating these works into the history of the Arabic novel, this book offers a transformative new account of modern Arabic literature, world literature, and the novel. This book rewrites the history of the global circulation of the novel by moving Arabic literature from the margins of comparative literature to its center. Considering the wide range of nineteenth- and early-twentieth-century translation practices, the book argues that Arabic translators did far more than copy European works; they authored new versions of them, producing sophisticated theorizations of the genre. These translations and the reading practices they precipitated form the conceptual and practical foundations of Arab literary modernity, necessitating an overhaul of our notions of translation, cultural exchange, and the global. The book shows how translators theorized the Arab world not as Europe's periphery but as an alternative center in a globalized network. It affirms the central place of (mis)translation in both the history of the novel in Arabic and the novel as a transnational form itself.

scholarly journals A novel flexible tool with rotary ultrasonic spindle for fine grinding of tungsten carbide

2018 ◽  
Vol 185 ◽  
pp. 00018
Author(s):  
Albert Wen-Jeng Hsue ◽  
Yi-Zhong Zheng
Keyword(s):  
Tungsten Carbide ◽  
The Novel ◽  
Machining Processes ◽  
Flexible Tool ◽  
Operational Conditions ◽  
Cnc Grinding ◽  
Grinding Conditions ◽  
Novel Design ◽  
Conventional Machining ◽  
Tungsten Steel

Tungsten carbide is a typical difficult-to-cut material by conventional machining processes. In this paper, a novel design of flexible abrasives tool combined with a rotary ultrasonic machining (RUM) spindle is conducted to reduce the labor force significantly. The newly designed flexibility of tool-tip is aimed at preventing overcutting from the CNC grinding. The grinding conditions with resulted surface morphology of the tungsten steel were investigated through Taguchi design of experiment and ANOVA analysis. The machining capability of the novel flexible tool is compared with conventional tools through specific grinding paths under proper operational conditions.

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