scholarly journals Tuning Physical Crosslinks in Hybrid Hydrogels for Network Structure Analysis and Mechanical Reinforcement

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 352 ◽  
Author(s):  
Xue Lv ◽  
Chuang Liu ◽  
Zhubao Shao ◽  
Shulin Sun
Keyword(s):  
Mechanical Strength ◽  
Large Scale ◽  
Mechanical Performance ◽  
Structural Parameters ◽  
Industrial Applications ◽  
Dissipated Energy ◽  
Small Scale ◽  
Hybrid Particles ◽  
Mechanical Reinforcement ◽  
Hybrid Hydrogels

Hydrogels with high mechanical strength are needed for a variety of industrial applications. Here, a series of hydrogels was prepared by introducing hybrid particles as hydrophobic association points to toughen the hydrogels. These toughened hydrogels were able to transfer an external mechanical force via the reorganization of the crosslinking networks. They exhibited an extraordinary mechanical performance, which was the result of the coordination between hydrophobic segments and hybrid particles. Herein, the connection between the dissipated energy of the inner distribution structure (on a small scale) and the mechanical properties (on a large scale) was conducted. Specifically, we inspected hydrogels of latex particles (LPs) with different chain lengths (C4, C12, C18) and studied their inner structural parameters, namely, the relationship between the density and molecular weight of crosslinking points to the mechanical strength and energy dissipation. Favorable traits of the hydrogels included compact internal structures that were basically free from defects and external structures with puncture resistance, high toughness, etc. Based on the experimental results that agreed with the theoretical results, this study provides a profound understanding of the internal structure of hydrogels, and it offers a new idea for the design of high-strength hybrid hydrogels.

scholarly journals Impinging jets – a short review on strategies for heat transfer enhancement

2018 ◽  
Vol 32 ◽  
pp. 01013
Author(s):  
Ilinca Nastase ◽  
Florin Bode
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Short Review ◽  
Great Difficulty ◽  
Impinging Jets ◽  
Industrial Applications ◽  
Experimental Investigations ◽  
Small Scale ◽  
Strong Shear ◽  
Flow Phenomena

In industrial applications, heat and mass transfer can be considerably increased using impinging jets. A large number of flow phenomena will be generated by the impinging flow, such as: large scale structures, large curvature involving strong shear and normal stresses, stagnation in the wall boundary layers, heat transfer with the impinged wall, small scale turbulent mixing. All these phenomena are highly unsteady and even if nowadays a substantial number of studies in the literature are dedicated, the impinging jets are still not fully understood due to the highly unsteady nature and more over due to great difficulty of performing detailed numerical and experimental investigations.

Small-angle scattering behavior of thread-like and film-like systems

2016 ◽  
Vol 49 (1) ◽  
pp. 260-276 ◽  
Author(s):  
Salvino Ciccariello ◽  
Pietro Riello ◽  
Alvise Benedetti
Keyword(s):  
Small Angle ◽  
Large Scale ◽  
Probability Function ◽  
Structural Parameters ◽  
Small Angle Scattering ◽  
Constant Thickness ◽  
Small Scale ◽  
Linear Segment ◽  
Angle Scattering ◽  
The Right

Film-like and thread-like systems are, respectively, defined by the property that one of the constituting homogenous phases has a constant thickness (δ) or a constant normal cross section (of largest chord δ). The stick probability function of this phase, in the limit δ → 0, naturally leads to the definition of the correlation function (CF) of a surface or of a curve. This CF closely approximates the generating stick probability function in the range of distances larger than δ. The surface and the curve CFs, respectively, behave as 1/rand as 1/r2asrapproaches zero. This result implies that the relevant small-angle scattering intensities behave as {\cal P}_{{\cal S}}/q^2 or as {\cal P}_{{\cal C}}/q in the intermediate range of the scattering vector magnitude (q) and as {\cal P}/q^4 in the outermostqrange. Similarly to {\cal P}, pre-factors {\cal P}_{{\cal S}} and {\cal P}_{{\cal C}} simply depend on some structural parameters. Depending on the scale resolution it may happen that a given sample looks thread like at large scale, film like at small scale and particulate at a finer scale. An explicit example is reported. As a practical illustration of the above results, the surface and the curve CFs of some simple geometrical shapes have been explicitly evaluated. In particular, the CF of the right circular cylinder is evaluated. Its limits, as the height or the diameter the cylinder approaches zero, are shown to coincide with the CFs of a circle and of a linear segment, respectively.

Magnetic Field-Assisted 3D Printing of Limpet Teeth Inspired Polymer Matrix Composite With Compression Reinforcement

2021 ◽  
Vol 144 (4) ◽  
Author(s):  
Dylan Joralmon ◽  
Evangeline Amonoo ◽  
Yizhen Zhu ◽  
Xiangjia Li
Keyword(s):  
Magnetic Field ◽  
3D Printing ◽  
Polymer Matrix ◽  
Mechanical Performance ◽  
Polymer Matrix Composites ◽  
Cost Effective ◽  
Industrial Applications ◽  
Mechanical Reinforcement ◽  
3D Printed ◽  
Geometric Morphology

Abstract Lightweight and cost-effective polymer matrix composites (PMCs) with extraordinary mechanical performance will be a key to the next generation of diverse industrial applications, such as aerospace, electric automobile, and biomedical devices. Limpet teeth made of mineral-polymer composites have been proved as nature’s strongest material due to the unique hierarchical architectures of mineral fiber alignment. Here, we present an approach to build limpet teeth inspired structural materials with precise control of geometric morphologies of microstructures by magnetic field-assisted 3D printing (MF-3DP). α-Iron (III) oxide-hydroxide nanoparticles (α-FeOOHs) are aligned by the magnetic field during 3D printing and aligned α-FeOOHs (aFeOOHs) bundles are further grown to aligned goethite-based bundles (aGBs) by rapid thermal treatment after printing. The mechanical reinforcement of aGBs in PMCs can be modulated by adjusting the geometric morphology and alignment of α-FeOOHs encapsulated inside the 3D printed PMCs. In order to identify the mechanical enhancement mechanism, physics-based modeling, simulation, and tests were conducted, and the results further guided the design of bioinspired goethite-based PMCs. The correlation of the geometric morphology of self-assembled α-FeOOHs, curing characteristics of α-FeOOHs/polymer composite, and process parameters were identified to establish the optimal design of goethite-based PMCs. The 3D printed PMCs with aGBs show promising mechanical reinforcement compared with PMCs without aGBs. This study opens intriguing perspectives for designing high strength 3D printed PMCs on the basis of bioinspired architectures with customized configurations.

Magnetic Field Assisted 3D Printing of Limpet Teeth Inspired Polymer Matrix Composite With Compression Reinforcement

2021 ◽  
Author(s):  
Dylan Joralmon ◽  
Evangeline Amonoo ◽  
Yizhen Zhu ◽  
Xiangjia Li
Keyword(s):  
Magnetic Field ◽  
3D Printing ◽  
Polymer Matrix ◽  
Mechanical Performance ◽  
Polymer Matrix Composites ◽  
Cost Effective ◽  
Industrial Applications ◽  
Mechanical Reinforcement ◽  
3D Printed ◽  
Geometric Morphology

Abstract Lightweight and cost-effective polymer matrix composites (PMCs) with extraordinary mechanical performance will be a key to the next generation of diverse industrial applications such as aerospace, electric automobile, and biomedical devices. Limpet teeth made of mineral-polymer composites have been proved as nature’s strongest material due to the unique hierarchical architectures of mineral fiber alignment. Here, we present an approach to build limpet teeth inspired structural materials with precise control of geometric morphologies of microstructures by magnetic field-assisted 3D printing (MF-3DP). α-Iron (III) oxide-hydroxide nanoparticles (α-FeOOHs) are aligned by the magnetic field during 3D printing and aligned α-FeOOHs bundles are further grown to aligned goethite-based bundles (aGBs) by rapid thermal treatment after printing. The mechanical reinforcement of goethite-based fillers in PMCs can be modulated by adjusting the geometric morphology and alignment of mineral particles encapsulated inside the 3D printed PMCs. In order to identify the mechanical enhancement mechanism, physics-based modeling, simulation, and tests were conducted and the results further guided the design of bioinspired goethite-based PMCs. The correlation of the geometric morphology of self-assembled α-FeOOHs, curing characteristics of α-FeOOHs/polymer composite, and process parameters were identified to establish the optimal design of goethite-based PMCs. The 3D-printed PMCs with aGBs show promising mechanical reinforcement. This study opens intriguing perspectives for designing high strength 3D printed PMCs on the basis of bioinspired architectures with customized configurations.

Soil–Geosynthetic Interface Shear in Different Testing Scales

2018 ◽  
Vol 2672 (52) ◽  
pp. 129-141 ◽  
Author(s):  
Gholam H. Roodi ◽  
Amr M. Morsy ◽  
Jorge. G. Zornberg
Keyword(s):  
Large Scale ◽  
Mechanical Performance ◽  
Shear Resistance ◽  
Reinforced Soil ◽  
Small Scale ◽  
Interface Shear ◽  
Shear Model ◽  
Wide Range ◽  
Scale Test ◽  
Large Scale Tests

Geosynthetics have been used to improve mechanical performance of roadway layers (e.g., geosynthetic-reinforced asphalt, geosynthetic-stabilized bases) and a wide range of transportation infrastructures (e.g., geosynthetic-reinforced soil walls). A key aspect in understanding soil–geosynthetic interaction mechanisms involved in each application includes characterization of the interface between geosynthetics and adjacent materials. This study evaluates soil–geosynthetic interface shear in various pullout test scales including standard, smaller than standard, and larger than standard scales. Experimental results obtained from tests conducted in each scale were analyzed to determine the soil–geosynthetic interface shear model. An iteration procedure, similar to that used in t–z analysis of pile loading, was developed to simulate incremental geosynthetic movements. Shape and parameters of the interface shear model were changed to minimize the residual error between experimental and simulated data. It was found that mobilization of the interface shear in the small-scale test differs from that in the standard- and large-scale tests. In the standard- and large-scale tests, the ultimate soil–geosynthetic interface shear mobilized at comparatively small displacements, which could be represented by a linear plastic interface shear model. In the small-scale test, however, the interface shear developed in two phases. A portion of the ultimate interface shear mobilized at comparatively small displacements while additional resistance continued to mobilize at extended displacements. Consequently, the development of interface shear resistance in the standard- and large-scale tests was found to depend on progressive increase of the geosynthetic mobilized length, whereas in the small-scale test the interface shear resistance developed by displacement of the entire geosynthetic.

scholarly journals Performance Evaluation of Fiber-Reinforced, Stress Relief Asphalt Layers to Suppress Reflective Cracks

2020 ◽  
Vol 10 (21) ◽  
pp. 7701
Author(s):  
Cheolmin Baek
Keyword(s):  
Surface Layer ◽  
Large Scale ◽  
Mechanical Performance ◽  
Asphalt Mixture ◽  
Base Layer ◽  
Scale Model ◽  
Small Scale ◽  
Fiber Reinforced ◽  
Stone Mastic Asphalt ◽  
Pavement Testing

In this study, the performance of the fiber-reinforced, stress-absorbing membrane interlayer (F-SAMI) method was evaluated to suppress reflective cracks, which usually occur when the overlay method is applied for the maintenance of existing aged pavement. The F-SAMI method has an effect of suppressing the occurrence of reflective cracks by constructing a material composed of emulsified asphalt, fibers, and aggregates between the surface layer and the base layer. The mechanical performance of the F-SAMI was evaluated through both small-scale (model mobile load simulator 3, or MMLS3) and large-scale (accelerated pavement testing, or APT) pavement acceleration tests on the specimen and pavement structures, respectively, with the F-SAMI layer applied between the surface layer and the base layer. In this study, the base layer was made with an asphalt mixture or a concrete mixture, and the surface layer was made with polymer-modified stone mastic asphalt (PSMA). Evaluation was conducted by applying four types of F-SAMI layer, according to the content of asphalt and aggregate and compared with the case where general tack coating was applied. In order to induce the occurrence of reflective cracks, a notch was made in the center of the base layer. As a result of the experiment, it was shown that regardless of the mixture type of the base layer, the specimen or pavement with the F-SAMI method was much more resistant to reflective cracking than those with the tack coating. In addition, it was found that the F-SAMI method with aggregates was more resistant to reflective cracks than that without aggregates.

Improving Productivity

2016 ◽  
Vol 4 (1) ◽  
pp. 43-62 ◽  
Author(s):  
Yudi Fernando ◽  
Anas Mathath ◽  
Mohsen Ali Murshid
Keyword(s):  
Food Industry ◽  
Large Scale ◽  
Material Handling ◽  
Service Sector ◽  
Production Systems ◽  
Food Service ◽  
Industrial Applications ◽  
Small Scale ◽  
Customer's Loyalty ◽  
Business Competitiveness

The role of robots is becoming substantial for industrial applications and business competitiveness. The purpose of this paper is to review robotic transformation concept and to investigate its business applications in the food industry. The robot transformation in food industry provided a robust support in raising business productivity, reduced cost and enhanced customer's loyalty, besides the food safety and quality. Its service in production systems for material handling and packaging operations is inevitable. Despite the importance of robotics in improving productivity, small scale food companies are often reluctant to invest in robotization of their operations. Since it involves high initial investment, maintenance and costs associated with training skilled employees for programming of robotics. Mainly, two points have raised concerns in the discussion of this paper. First, the robot technology has been enhanced to deliver services for the large scale food companies. Meanwhile, the experiences gained in the food service sector which implement robots can replace the human touch. At the end of this review, several solutions are recommended to shed light on the applications of the robot in the food industry.

Onset of Flow Induced Tonal Noise in Corrugated Pipe Segments

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Oleksii Rudenko ◽  
Güneş Nakiboğlu ◽  
Avraham Hirschberg
Keyword(s):  
Large Scale ◽  
Wave Length ◽  
Industrial Applications ◽  
Small Scale ◽  
Tonal Noise ◽  
Pipe Length ◽  
Composite Pipe ◽  
Pipe Segment ◽  
Smooth Pipe ◽  
High Reynolds

Corrugated pipes combine small-scale rigidity and large-scale flexibility, which make them very useful in industrial applications. The flow through such a pipe can induce strong undesirable tonal noise (whistling) and even drive integrity threatening structural vibrations. Placing a corrugated segment along a smooth pipe reduces the whistling, while this composite pipe still retains some global flexibility. The whistling is reduced by thermoviscous damping in the smooth pipe segment. For a given corrugated segment and flow velocity, one would like to predict the smooth pipe length just sufficient to avoid tonal noise: the onset of whistling. A linear model based on empirical data is proposed that predicts the conditions at the onset of whistling for a composite pipe at moderately high Reynolds numbers, Re: 3000<Re<100,000. Experimental results for corrugated pipes of eight different corrugation geometries are presented revealing fair agreement with the theory. Based on these results, a universal qualitative prediction tool is obtained valid for corrugated pipe segments long compared to the acoustic wave-length.

scholarly journals Axially loaded grouted connections in offshore conditions using ordinary portland cement

2018 ◽  
Author(s):  
Joshua Henneberg ◽  
Peter Schaumann ◽  
Alexander Raba
Keyword(s):  
Portland Cement ◽  
Large Scale ◽  
Ordinary Portland Cement ◽  
Mechanical Performance ◽  
Production Costs ◽  
Offshore Wind ◽  
Small Scale ◽  
Filling Material ◽  
Ambient Conditions ◽  
Steel Tubes

A grouted connection (GC) is a hybrid connection which joins two telescoped steel tubes by filling the annulus between the steel tubes with grout. GCs are frequently used to enable a force fitted connection between piles and substructure of offshore wind turbines. At latticed substructures this connection is located at mudline level in wet ambient conditions (AC). Nowadays special grout materials are used to achieve not only best mechanical properties but also a good performance during grouting in offshore conditions.To reduce production costs the use of ordinary portland cement (OPC) is investigated as an alternative filling material within this paper. OPC has a much lower tendency to segregate, as there are no aggregates added. This leads to more simplified, stable and cheaper production processes offshore. Further focus is put on the failure mode of OPC filled GCs in submerged condtions.For an appropriate use of OPC offshore a feasible mechanical performance needs to be ensured. Investigating this, small and large-scale laboratory tests were performed at Leibniz Universität Hannover. Using the experimental test setup of previous investigations for special high performance grouts (HPG) [1, 2], enables a direct comparison of HPG and OPC. Documenting liquid and solid OPC properties, like slump flow and compressive strength confirms a stable material quality. Small-scale ULS-tests showed significantly lower ULS-capacities and a more brittle failing process compared to HPG. Lagre-scale tests confirmed the observed failure mechanisms of Schaumann and Raba for OPC filled GCs in submerged conditions [3]. Carried out tests showed significant influence of grout material and confirmed influence of grout annulus size on fatigue capacity.

A Linear Model for the Onset of Whistling in Corrugated Pipe Segments: Influence of Geometry

2013 ◽  
Author(s):  
Oleksii Rudenko ◽  
Dennis Meertens ◽  
Güneş Nakiboğlu ◽  
Avraham Hirschberg ◽  
Stefan Belfroid
Keyword(s):  
Large Scale ◽  
Reynolds Numbers ◽  
Industrial Applications ◽  
Small Scale ◽  
Composite Pipe ◽  
Pipe Segment ◽  
Flow Through ◽  
Smooth Pipe ◽  
High Reynolds ◽  
Semi Empirical

Corrugated pipes combine small-scale rigidity and large-scale flexibility, which makes them very useful in industrial applications. The flow through such a pipe can induce strong undesirable whistling noises and even drive dangerous structural vibrations. Placing a short corrugated segment along a smooth pipe reduces the whistling, while this composite pipe still retains some global flexibility. The whistling is reduced by thermo-viscous damping in the smooth pipe segment. A linear semi-empirical model is proposed that allows to predict the critical Mach numbers at the onset of whistling for a composite pipe at moderately high Reynolds numbers. Experimental results for corrugated pipes of three different corrugations geometries are presented revealing fair agreement with the theory. In addition, the model indicates that even for a corrugated pipe segment with an anechoic termination, corresponding to a very long smooth pipe segment, there exists a finite critical Mach number above which the whistling occurs.

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