scholarly journals Integrated dynamic wet spinning of core-sheath hydrogel fibers for optical-to-brain/tissue communications

2020 ◽  
Author(s):  
Guoyin Chen ◽  
Gang Wang ◽  
Xinrong Tan ◽  
Kai Hou ◽  
Qingshuo Meng ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Optical Fibers ◽  
Rational Design ◽  
Large Scale ◽  
Young's Modulus ◽  
Solution Viscosity ◽  
Wet Spinning ◽  
Deep Tissue ◽  
Optogenetic Stimulation ◽  
Tissue Therapy

Abstract Hydrogel optical light-guides have received substantial interest for applications such as deep-tissue biosensors, optogenetic stimulation and photomedicine due to their biocompatibility, (micro)structure control and tissue-like Young's modulus. However, despite recent developments, large-scale fabrication with a continuous synthetic methodology, which could produce core-sheath hydrogel fibers with the desired optical and mechanical properties suitable for deep-tissue applications, has yet to be achieved. In this study, we report a versatile concept of integrated light-triggered dynamic wet spinning capable of continuously producing core-sheath hydrogel optical fibers with tunable fiber diameters, and mechanical and optical propagation properties. Furthermore, this concept also exhibited versatility for various kinds of core-sheath functional fibers. The wet spinning synthetic procedure and fabrication process were optimized with the rational design of the core/sheath material interface compatibility [core = poly(ethylene glycol diacrylate-co-acrylamide); sheath = Ca-alginate], optical transparency, refractive index and spinning solution viscosity. The resulting hydrogel optical fibers exhibited desirable low optical attenuation (0.18 ± 0.01 dB cm−1 with 650 nm laser light), excellent biocompatibility and tissue-like Young's modulus (<2.60 MPa). The optical waveguide hydrogel fibers were successfully employed for deep-tissue cancer therapy and brain optogenetic stimulation, confirming that they could serve as an efficient versatile tool for diverse deep-tissue therapy and brain optogenetic applications.

scholarly journals Approximate Dynamic Programming Based Control of Proppant Concentration in Hydraulic Fracturing

Mathematics ◽  
2018 ◽  
Vol 6 (8) ◽  
pp. 132 ◽  
Author(s):  
Harwinder Singh Sidhu ◽  
Prashanth Siddhamshetty ◽  
Joseph Kwon
Keyword(s):  
Mechanical Properties ◽  
Dynamic Programming ◽  
Hydraulic Fracturing ◽  
Young’S Modulus ◽  
Large Scale ◽  
Approximate Dynamic Programming ◽  
Young's Modulus ◽  
Computational Cost ◽  
Control Technique ◽  
Rock Mechanical Properties

Hydraulic fracturing has played a crucial role in enhancing the extraction of oil and gas from deep underground sources. The two main objectives of hydraulic fracturing are to produce fractures with a desired fracture geometry and to achieve the target proppant concentration inside the fracture. Recently, some efforts have been made to accomplish these objectives by the model predictive control (MPC) theory based on the assumption that the rock mechanical properties such as the Young’s modulus are known and spatially homogenous. However, this approach may not be optimal if there is an uncertainty in the rock mechanical properties. Furthermore, the computational requirements associated with the MPC approach to calculate the control moves at each sampling time can be significantly high when the underlying process dynamics is described by a nonlinear large-scale system. To address these issues, the current work proposes an approximate dynamic programming (ADP) based approach for the closed-loop control of hydraulic fracturing to achieve the target proppant concentration at the end of pumping. ADP is a model-based control technique which combines a high-fidelity simulation and function approximator to alleviate the “curse-of-dimensionality” associated with the traditional dynamic programming (DP) approach. A series of simulations results is provided to demonstrate the performance of the ADP-based controller in achieving the target proppant concentration at the end of pumping at a fraction of the computational cost required by MPC while handling the uncertainty in the Young’s modulus of the rock formation.

scholarly journals Dynamic Radiation Effects Induced by Short-Pulsed GeV U-Ion Beams in Graphite and h-BN Targets

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Philipp Bolz ◽  
Philipp Drechsel ◽  
Alexey Prosvetov ◽  
Pascal Simon ◽  
Christina Trautmann ◽  
...  
Keyword(s):  
Boron Nitride ◽  
Young’S Modulus ◽  
Radiation Effects ◽  
Large Scale ◽  
Hexagonal Boron Nitride ◽  
Young's Modulus ◽  
Target Surface ◽  
High Dose ◽  
Velocity Signal ◽  
Isotropic Graphite

Targets of isotropic graphite and hexagonal boron nitride were exposed to short pulses of uranium ions with ∼1 GeV kinetic energy. The deposited power density of ∼3 MW/cm³ generates thermal stress in the samples leading to pressure waves. The velocity of the respective motion of the target surface was measured by laser Doppler vibrometry. The bending modes are identified as the dominant components in the velocity signal recorded as a function of time. With accumulated radiation damage, the bending mode frequency shifts towards higher values. Based on this shift, Young’s modulus of irradiated isotropic graphite is determined by comparison with ANSYS simulations. The increase of Young’s modulus up to 3 times the pristine value for the highest accumulated fluence of 3 × 1013 ions/cm2 is attributed to the beam-induced microstructural evolution into a disordered structure similar to glassy carbon. Young’s modulus values deduced from microindentation measurements are similar, confirming the validity of the method. Beam-induced stress waves remain in the elastic regime, and no large-scale damage can be observed in graphite. Hexagonal boron nitride shows lower radiation resistance. Circular cracks are generated already at low fluences, risking material failure when applied in high-dose environment.

Wet-Spinning of Reinforced Artificial Silk Hybrid Fibres by Cellulose Whiskers

2011 ◽  
Vol 175-176 ◽  
pp. 272-275 ◽  
Author(s):  
Lin Liu ◽  
Ju Ming Yao
Keyword(s):  
Aqueous Solution ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Room Temperature ◽  
Young's Modulus ◽  
Wet Spinning ◽  
Hybrid Fibers ◽  
Characteristic Index ◽  
Cellulose Whiskers ◽  
Cellulose Whisker

In this paper, the cellulose whisker/silk fibroin (CW/SF) aqueous solution with different composition was obtained by a dialysis against polyethylene glycol (PEG) solution at room temperature. The rheological behavior of CW/SF solution was investigated and the reinforced CW/SF hybrid fibres were prepared by a dry-wet spinning method. The results showed that the spinnability was better for the CW/SF solution according to the calculation of flowing characteristic index. The cellulose whiskers were dispersed homogeneously in the silk matrix. Moreover, it could be found that the tensile strength and Young’s modulus of the hybrid fibers were improved with the increase of cellulose whisker content, which reached the maximum when the cellulose whisker content was 5 wt%. Compared with the pure silk fiber, the tensile strength and Young’s modulus of the CW/SF hybrid fibers containing 5 wt% CWs were increased from 135.78±12.73 MPa and 5.74±0.43 GPa to 438.68±22.63 MPa and 17.36±2.04 GPa, respectively.

Advanced Optimization of Industrial Large-Scale Roll-to-Roll Systems Under Parametric Uncertainties

2012 ◽  
Author(s):  
J. Frechard ◽  
D. Knittel
Keyword(s):  
Young’S Modulus ◽  
Large Scale ◽  
Young's Modulus ◽  
Robust Design Optimization ◽  
Parametric Uncertainties ◽  
Optimization Approach ◽  
Roll To Roll ◽  
Polymer Metal ◽  
The Web ◽  
Web Tension

In industrial plants some parameters can not be evaluated properly or they are varying with time. These parametric uncertainties has to be taken into account during the design process of industrial systems. In this work, the developped optimization approach is applied on an industrial roll-to-roll sytem. Such systems are commonly used to handle materials as polymer, metal, paper and textile. The key challenge is to move the web at the expected speed while maintaining the web tension in an acceptable range around its reference. Moreover, the Young’s modulus of the web is difficult to evaluate and it is varying with time due to temperature and moisture variations. This paper deals with the web tension controller synthesis on a large-scale roll-to-roll system with uncertain Young’s modulus. To synthesize web tension controllers, an H∞ approach is applied and adapted to the system with parametric uncertainties using multi-objective robust design optimization.

Development of Porous Material with High Young’s Modulus and Low Thermal Expansion Coefficient in SiC-Vitrified Bonding Material-LiAlSiO4 System

2009 ◽  
Vol 620-622 ◽  
pp. 715-718 ◽  
Author(s):  
Tatsuya Ono ◽  
Koji Matsumaru ◽  
Isaías Juárez-Ramírez ◽  
Leticia M. Torres-Martínez ◽  
Kozo Ishizaki
Keyword(s):  
Thermal Expansion ◽  
Porous Material ◽  
Porous Materials ◽  
Young’S Modulus ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Large Scale ◽  
Young's Modulus ◽  
Negative Thermal Expansion ◽  
Low Thermal Expansion

Machines for manufacturing large scale flat displays are enlarging as the size of glasses increases. This work develops porous materials with a low thermal expansion coefficient and a high Young’s modulus. SiC and LiAlSiO4 were used for a positive and a negative thermal expansion materials, respectively. Compositions of powders for porous materials were determined to obtain a desirable Young’s modulus and thermal expansion coefficient by using SiC-VBM-LiAlSiO4 phase diagram at 20 % of porosity. The empirical values of Young’s modulus and a thermal expansion coefficient are close to the theoretical values by using the diagram. Fabricated porous material had high enough Young’s modulus of 87 GPa, and low enough thermal expansion coefficient of 2 x 10-6 K-1 at temperatures ranging from -17 °C to 190 °C with 22 % of porosity.

Investigation into the Dynamic Fracture Properties of Large Scale Functionally Graded Materials

2006 ◽  
Vol 324-325 ◽  
pp. 239-242 ◽  
Author(s):  
Xiao Bin Yang ◽  
Zhuo Zhuang ◽  
Xue Feng Yao
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Large Scale ◽  
Young's Modulus ◽  
Mass Density ◽  
Poisson's Ratio ◽  
Constant Mass ◽  
Functionally Gradient Materials ◽  
Gradient Materials ◽  
Functionally Gradient

A crack propagation perpendicular to gradient in a large scale functionally gradient materials, which has (1) a linear variation of Young’s modulus with a constant mass density and Poisson’s ratio, and (2) a exponential variation of Young’s modulus with a constant mass density and Poisson’s ratio, is modelled by finite element methods. Based on the experimental result of large scale functionally gradient materials, the dynamic propagation process of the FGMs is modelled and the dynamic parameters, like the energy release rate and crack tip opening angle, are calculated through a generation phase.

scholarly journals The Impact of Shear and Elongational Forces on Structural Formation of Polyacrylonitrile/Carbon Nanotubes Composite Fibers during Wet Spinning Process

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2797 ◽  
Author(s):  
Hamideh Mirbaha ◽  
Parviz Nourpanah ◽  
Paolo Scardi ◽  
Mirco D’incau ◽  
Gabriele Greco ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Young’S Modulus ◽  
Shear Force ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Wet Spinning ◽  
Composite Fibers ◽  
Pan Fibers ◽  
Spun Fibers

Wet spinning of polyacrylonitrile/carbon nanotubes (PAN/CNT) composite fibers was studied and the effect of spinning conditions on structure and properties of as-spun fibers influenced by the presence of CNTs investigated. Unlike PAN fibers, shear force had a larger effect on crystalline structure and physical and mechanical properties of PAN/CNT composite fibers compared to the elongational force inside a coagulation bath. Under shear force CNTs induced nucleation of new crystals, whereas under elongational force nucleation of new crystals were hindered but the already formed crystals grew bigger. To our knowledge, this key effect has not been reported elsewhere. At different shear rates, strength, Young’s modulus and strain at break of PAN/CNT as-spun fibers were improved up to 20% compared to PAN fibers. Application of jet stretch had less influence on physical and mechanical properties of PAN/CNT fibers compared to PAN fibers. However, the improvement of interphase between polymer chains and CNTs as a result of chain orientation may have contributed to enhancement of Young’s modulus of jet stretched composite fibers.

High Precision Young’s Modulus Extraction of Thin Films Through Measuring the Electric-Circuit Behavior of Microstructures

2005 ◽  
Author(s):  
Yuh-Chung Hu ◽  
Wei-Hsin Gau ◽  
Wei-Hsiang Tu
Keyword(s):  
Thin Films ◽  
Young’S Modulus ◽  
High Precision ◽  
Large Scale ◽  
Crystalline Silicon ◽  
Young's Modulus ◽  
Electric Circuit ◽  
Extraction Methods ◽  
Voltage Measurement ◽  
Wafer Level

This paper is aimed at developing a high precision algorithm for extracting the Young’s modulus of thin films through the capacitance-voltage measurement of microstructures at wafer level. Two flat micro cantilever beams made of single crystalline silicon are demonstrated. The average value of extracted Young’s modulus in (110) crystalline plane by the present methodology is about 169 GPa, compared to the well-defined value of 168 GPa, the error percentage is within 1% and the high precision and repeatability of the present methodology are verified. Since the driving and measuring signals of the present methodology are both electric, they could be accomplished using existing semiconductor testing equipments through probing on the bonding pads of devices. Because hardware replacement could be avoided, the present methodology shows substantial advantage over other property-extraction methods for large-scale implementation in semiconductor or MEMS fabs.

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