scholarly journals Engineered Electrospun Polyurethane Composite Patch Combined with Bi-functional Components Rendering High Strength for Cardiac Tissue Engineering

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 705 ◽  
Author(s):  
Mohan Mani ◽  
Saravana Jaganathan ◽  
Ahmad Faudzi ◽  
Mohd Sunar

Cardiovascular application of nanomaterial’s is of increasing demand and its usage is limited by its mechanical and blood compatible properties. In this work, an attempt is made to develop an electrospun novel nanocomposite loaded with basil oil and titanium dioxide (TiO2) particles. The composite material displayed increase in hydrophobic and reduced fiber diameter compared to the pristine polymer. Fourier transform infrared spectroscopy results showed the interaction of the pristine polymer with the added substances. Thermal analysis showed the increased onset degradation, whereas the mechanical testing portrayed the increased tensile strength of the composites. Finally, the composite delayed the coagulation times and also rendered safe environment for red blood cells signifying its suitability to be used in contact with blood. Strikingly, the cellular toxicity of the developed composite was lower than the pristine polymer suggesting its compatible nature with the surrounding tissues. With these promising characteristics, developed material with enhanced physicochemical properties and blood compatibility can be successfully utilized for cardiac tissue applications.

2012 ◽  
Vol 706-709 ◽  
pp. 2181-2186 ◽  
Author(s):  
Tulio M.F. Melo ◽  
Érica Ribeiro ◽  
Lorena Dutra ◽  
Dagoberto Brandão Santos

The increasing demand, mainly from the automobile industry, for materials which combine high strength, high ductility and low specific weight makes steels with the TWIP (TWinning Induced Plasticity) effect a promising material to meet these requirements. This work aimed to study the kinetics of isothermal recrystallization of a TWIP steel (C-0.06%, Mn-25%, Al-3%, Si-2%, and Ni-1%) after cold rolling. The steel was hot and cold-rolled and then annealed at 700°C with soaking times ranging from 10 to 7200 s. Microstructural analysis was performed using light (LM) and scanning electron microscopy (SEM). Furthermore, quantitative metallography was performed in order to evaluate the recrystallized volume fraction and grain size. A JMAK based model was applied to describe the nucleation grain growth process. The restoration of the steel was also evaluated by microhardness tests. A complete recrystallization after 7200 s at 700°C was observed. It was found that with increasing annealing times, the recrystallized volume fraction also increases, while the nucleation and growth rates decrease, in agreement with the results for plain carbon steels.


Author(s):  
Diego Belato Rosado ◽  
Wim De Waele ◽  
Dirk Vanderschueren ◽  
Stijn Hertelé

In response to the increasing demand to improve both transportation efficiency and performance, the steel pipe industry has conducted extensive efforts to develop line pipe steel grades with superior metallurgical and mechanical (strength, toughness and ductility) properties in order to allow exploitation in hostile environments. This paper aims to give an overview of recent developments of high strength pipe steel grades as API 5L X70 and beyond, providing a detailed understanding of the continuous improvements with respect to a strain-based design context. Information regarding the metallurgy and processing, such as chemical composition, microstructural design, thermo-mechanical controlled process (TMCP) and accelerated cooling process (AcC), to achieve the target strength, ductility and toughness properties are discussed.


Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 165 ◽  
Author(s):  
Jingchuan Liu ◽  
Mengqi Zhang ◽  
Fengchun Jiang ◽  
Lan Zhang ◽  
Liquan Wang ◽  
...  

An innovative, high-strength metal–intermetallic-laminate (MIL) composite Ti-(SiCf/Al3Ti), reinforced by double or even several SiC fiber rows, was fabricated. A high-efficiency, semi-analytical model with a numerical equivalent inclusion method (NEIM) was employed to investigate the deformation behaviors, microscopic strengthening, and failure mechanisms of the composite during elasto-plastic sphere–plane contact. The microstructure and interface features were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The contact model for the Ti-(SiCf/Al3Ti) composite was validated via quasi-static compressive indentation tests with a spherical indenter. A series of in-depth parametric studies were conducted to quantify the effect of the microstructure. The results indicate that the as-fabricated laminated composite has a well-organized microstructure and a higher volume fraction of fibers. The SiC fiber rows effectively enhance the strength and toughness of the composite. The optimal diameter of the SiC fibers is 32 μm when the horizontal center distance between the adjacent fibers is 2.5 times that of the fiber diameter. The hole defects occurring above the fibers would damage the material strength most compared with those occurring in other positions. The optimal quantity of the SiC fiber rows is four when the thickness of the SiCf/Al3Ti layer is 400 μm and the fiber diameter is 8 μm.


2019 ◽  
Vol 28 (4) ◽  
pp. 233-241
Author(s):  
Saravana Kumar Jaganathan ◽  
Mohan Prasath Mani

One of the greatest challenges in the bone remodeling is to fabricate the structure resembling the extracellular matrix. This research aims to fabricate a novel bone scaffold comprising polyurethane (PU) added with almond nanofibers via electrospinning technique. The PU/almond oil nanocomposites showed smaller fiber diameter (629 ± 148.92 nm) compared to the pristine PU (890 ± 116.91 nm). The interaction of PU with almond oil was confirmed in the infrared spectrum by the strong formation of a hydrogen bond. The wettability analysis showed that the prepared PU/almond oil nanocomposites were hydrophobic in nature (107° ± 1) compared with the pure PU (100° ± 0.5774). Thermal analysis revealed enhancement of the thermal stability with the addition of the almond oil. The addition of almond oil into the PU matrix increased the surface roughness and blood compatibility properties. Further, the fabricated PU/almond oil nanocomposites showed less toxicity to red blood cells (RBCs), as indicated in the hemolytic assay. Hence, the novel fabricated scaffold possesses better physicochemical properties and is nontoxic to the RBCs, which may be utilized for bone tissue regeneration.


2017 ◽  
Vol 135 (3) ◽  
pp. 45691 ◽  
Author(s):  
Saravana Kumar Jaganathan ◽  
Mohan Prasath Mani ◽  
Manikandan Ayyar ◽  
Navaneetha Pandiyaraj Krishnasamy ◽  
Gomathi Nageswaran

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1381 ◽  
Author(s):  
Pereira ◽  
Fernandes ◽  
Morais ◽  
Quintão

Welding is a fundamental process in many industries. It is a fast-changing technology, continuously evolving, with recent developments in laser and robotic welding, virtual reality and machine learning. Focusing on laser welding, there is a significant interest in this technology, as well as an increasing demand for high-strength lightweight structures, replacing metals in some applications. This work presents an experimental study of the mechanical properties of three types of polyamide 6 joints welded by Nd:YAG laser. After welding, tensile tests were carried out in order to evaluate the influence of the joint type and weld passes on joint strength and weld stresses. The results showed that fairly high weld stresses could be achieved, indicating that good-quality welds were achieved.


2014 ◽  
Vol 556-562 ◽  
pp. 6803-6806
Author(s):  
Yi Jun Ran ◽  
Ying Xiao

With the wide application of the fixed telephone services and the increasing demand from enterprises and institutions, based on the unified payment platform to purchase an electronic lottery system, a system which is based on browser/server structure, developed modelling on the MVC (Model - View - Controller) design pattern, and is mainly based on the design and development of a unified payment platform, unified payment that falls into such categories as business management, payment engine, the three-channel gateway, in the form of various functional components of an abstract package and through the process engineering series for each function processing chain. Abstract business differences in parametric configuration, defined business processes through product configuration, in a unified channel gateways for different formats, different standards for each channel to send and receive packets processed. Under the unified payment System developed web payment lottery, fixed telephone payment lottery, data acquisition synchronization summary, and simulation billing functions.


2014 ◽  
Vol 611-612 ◽  
pp. 1413-1420 ◽  
Author(s):  
Marion Merklein ◽  
Gerson Meschut ◽  
Martin Müller ◽  
Réjane Hörhold

Facing a decreasing amount of resources on the one hand and an increasing demand for comfort on the other, more and more attention is being paid to sustainability and care for the environment. Particularly in the automotive sector, lightweight design principles continue to prosper rapidly. As a result, adjusted materials for different applications were developed. Due to the formation of intermetallic phases, most multi-material mixes cannot be welded and require adapted joining technologies. Mechanical joining technologies such as self-piercing riveting and mechanical clinching have proven effective methods of joining lightweight materials like aluminium and ductile steels. New high-strength steels are increasingly used in crash-sections, where limited deformation under impact load is required. These hot stamped steels have a very low elongation at break and therefore a low formability. Currently there is no joining by forming technology without pre-punching available using these grades of steels on die-side. The newly developed shear-clinching process is one possible method of joining this kind of material without additional elements. The fundamental idea of shear-clinching is a single-stage process in which pre-punching of the die-side material is performed by indirect shear-cutting and subsequent forming of the upper layer into this hole. This would immensely enlarge the application segment of mechanical clinching even if hot stamped steels are positioned on die-side. Fundamental studies are required to ensure process reliability and it is necessary to break down the joining process into fragments, like pre-punching and clinching with pre-punched sheet, and superpose them to form the combined procedure shear-clinching. This paper presents a detailed investigation of the sub-process clinching with pre-hole.


2010 ◽  
Vol 152-153 ◽  
pp. 212-217 ◽  
Author(s):  
Shao Min Song ◽  
Juan Hong Liu ◽  
Lin Wang

With the increasing demand for high strength concrete, more attention has been paid to the problem of high viscosity mixture in high strength concrete technology by academic and engineering circles. This project studied the effects of ultra-fine limestone powder on the workability and viscosity of fresh concrete using the ultra-fine limestone powder (LP) obtained by ultra-fine grinding of limestone powder, building sandstone processing waste, as fine mineral admixture of high strength concrete. The experimental results show that the viscosity of fresh high strength concrete with ultra-fine limestone powder decreases significantly. At the same time, the influence of ultra-fine limestone powder on the strength of the concrete at different ages is very little.


Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8381
Author(s):  
Liya Tom ◽  
Muhammad Khowja ◽  
Gaurang Vakil ◽  
Chris Gerada

Electric and hybrid-electric aircraft propulsion are rapidly revolutionising mobility technologies. Air travel has become a major focus point with respect to reducing greenhouse gas emissions. The electrification of aircraft components can bring several benefits such as reduced mass, environmental impact, fuel consumption, increased reliability and quicker failure resolution. Propulsion, actuation and power generation are the three key areas of focus in more electric aircraft technologies, due to the increasing demand for power-dense, efficient and fault-tolerant flight components. The necessity of having environmentally friendly aircraft systems has promoted the aerospace industry to use electrically powered drive systems, rather than the conventional mechanical, pneumatic or hydraulic systems. In this context, this paper reviews the current state of art and future advances in more electric technologies, in conjunction with a number of industrially relevant discussions. In this study, a permanent magnet motor was identified as the most efficient machine for aircraft subsystems. It is found to be 78% and 60% more power dense than switch-reluctant and induction machines. Several development methods to close the gap between existing and future design were also analysed, including the embedded cooling system, high-thermal-conductivity insulation materials, thin-gauge and high-strength electrical steel and integrated motor drive topology.


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