This book in the emerging research field of biomaterials covers biodegradable metals for biomedical applications. The book contains two main parts where each of them consists of three chapters. The ...first part introduces the readers to the field of metallic biomaterials, exposes the state of the art of biodegradable metals, and reveals its application for cardiovascular implants. Some fundamental aspects to give basic understanding on metals for further review on the degradable ones is covered in chapter one. The second chapter introduces the concept of biodegradable metals, it's state of the art and discuses a shifted paradigm from inert to bioactive, from corrosion resistant to corrodible metals. The third chapter focuses on the challenges and opportunities of using biodegradable metals for cardiovascular applications. The second part exposes an example of biodegradable metals from its concept to applications where a complete study on metallic biodegradable stent is detailed from materials design, development, testing till the implant fabrication. The forth chapter reveals new alloys development devoted for metallic biodegradable stent based on required criteria derrived from clinical needs and current nondegradable stents properties. Degradation of the alloys in simulated arterial conditions and its effect to cells are exposed in chapter five. The both chapters are concluded with a benchmarking of some more recent researches on materials development and testing for biodegradable stents. Chapter six reveals the tranformation process of the materials into stent prototypes where a standard process for making 316L stainless steel stents was followed. The book is completed by a perspective on the use of biodegradable metals for biomedical applications in the era of tissue engineering.
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Material extrusion (MEX) of complex thermoplastic structures often depends on the reliable printing of a water-soluble support structure. The material of choice is typically polyvinyl alcohol (PVA), ...which is not used in ceramic MEX printing due to a limited printing compatibility with most ceramic feedstocks (poor layer adhesion). Herein, a new thermoplastic feedstock was developed as temporary support material on the basis of NaCl mixed with a commercial injection molding binder system. The NaCl feedstock is fully compatible for MEX printing with ceramic feedstocks and showed excellent printing properties and high green body strength. The support structure is mostly dissolved in water and the rest can be removed manually or during thermal debinding. The NaCl support material was used to print flexible Al2O3 samples with hinges or chainmail samples. This strategy is an attractive way to introduce additional functionality and new applications which were so far inaccessible to technical ceramics.
•NaCl composite support material for MEX 3D printing of complex ceramic parts.•NaCl composite feedstock is compatible with ceramic feedstocks for multi-material printing.•MEX with ceramic injection molding feedstocks.•Flexible interconnected hinges, chains and meshes 3D printed from Al2O3.
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This article proposes a four-variable shear deformation refined beam theory for thermo-mechanical vibration characteristics of porous, functionally graded (FG) beams exposed to various kinds of ...thermal loadings by using an analytical method. Thermo-mechanical properties of functionally graded material (FGM) beams are supposed to vary through the thickness direction, and are estimated through the modified power-law rule in which the porosities with even and uneven types are approximated. The material properties of FGM beams are supposed to be temperature dependent. Porosities possibly occur inside FGMs during fabrication because of technical problems that lead to the creation of microvoids in these materials. The variation of pores along the thickness direction influences the mechanical properties. Thus, it is incumbent to predict the effect of porosities on the thermo-mechanical vibration behavior of FG beam in the present study. Four types of thermal loading, namely, uniform, linear, nonlinear, and sinusoidal temperature rises through the z-axis direction are discussed. The governing differential equations and boundary conditions of FG porous beams subjected to thermal loadings are formulated through Hamilton's principle, based on a four-variable refined theory that considers a constant transverse displacement and higher order variation of axial displacement through the depth of the beam without the need of any shear correction factors. An analytical solution procedure is used to achieve the natural frequencies of porous FG beams subjected to various temperature fields. The impact of several specific parameters such as power-law exponent, porosity volume fraction, different porosity distribution, and thermal effect on the vibration of the porous FG beams is perused and discussed in detail. It is deduced that these parameters play a notable role on the thermo-dynamic behavior of porous FG beams. Presented numerical results can serve as benchmarks for the future analyses of FG beams with porosity phases.
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Since the Material Genome Initiative (MGI) was proposed, high-throughput based technology has been widely employed in various fields of materials science. As a theoretical guide, material informatics ...has been introduced based on machine learning and data mining and high-throughput computation has been employed for large scale search, narrowing down the scope of the experiment trials. High-throughput materials experiments including synthesis, processing, and characterization technologies have become valuable research tools to pin down the prediction experimentally, enabling the discovery-to-deployment of advances materials more efficiently at a fraction of cost. This review aims to summarize the recent advances of high-throughput materials experiments and introduce briefly the development of materials design based on material genome concept. By selecting representative and classic works in the past years, various high-throughput preparation methods are introduced for different types of material gradient libraries, including metallic, inorganic materials, and polymers. Furthermore, high-throughput characterization approaches are comprehensively discussed, including both their advantages and limitations. Specifically, we focus on high-throughput mass spectrometry to analyze its current status and challenges in the application of catalysts screening.
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In view of the significant increase in research activity and publications in functionally graded materials (FGMs) and structures in the last few years, the present article is an attempt to identify ...and highlight the topics that are most relevant to FGMs and structures and review representative journal publications that are related to those topics. A critical review of the reported studies in the area of thermo-elastic and vibration analyses of functionally graded (FG) plates with an emphasis on the recent works published since 1998. Because of the extensive growth in the body of knowledge in FGMs in the last two decades, it is prudent to reduce the review to a manageable level by concentrating on the FG plate problems only. The review carried out here, is concerned with deformation, stress, vibration and stability problems of FG plates. This review is intended to give the readers a feel for the variety of studies and applications related to graded composites. An effort has been made here, to include all the important contributions in the current area of interest. The critical areas regarding future research needs for the successful implementation of FGM in design are outlined in the conclusions.
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•Review the flexibility and stretchability of piezoelectric materials.•Overview on piezoelectric effects, fabrication schemes, and performance of sensors.•Recommend materials and ...structures for human physiological signal monitoring, motion detection, and force sensing.•Provide future prospects of piezotronics.
Self-powered devices and micro-sensors are in high demand for intelligent electronics and flexible wearables for applications in medical healthcare and human–computer interactive robotics. Flexible, stretchable, wearable and breathable high-sensitivity sensors that monitor signals from subtle changes in the environment provide solutions for personalized medical healthcare. In this article, we review the fundamental mechanisms, theoretical research, sensor fabrication methodologies, and applications of flexible piezoelectric materials. We focus on the flexibility and stretchability of inorganic, polymer, and bio-piezoelectric materials, explain their properties for physiological signal monitoring, motion detection, and force sensing. We provide an overview of the latest progress in piezoelectronics and piezoelectric photonics, the structures of devices, and self-powering technologies. We compared 10 types of polymers and composites with human skin in terms of elastic modulus and found that PLLA/PDMS, electro-spun PVDF, and ZnO/PVDF possess higher elastic modulus (50, 500, and 27900 MPa respectively) than human skin (18.8 MPa), thus being more suitable for wearable devices. In terms of electrical outputs of piezoelectric materials, polarized cast film has stronger piezoelectric property with output of 14–45.6 V than electro-spun filaments material (output 0.4–9 V). Future research and development should focus on increasing electrical performance while maintaining the required flexibility and durability.
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Functionally graded materials (FGMs) have attracted much research interest in the industry due to their graded material properties, which result from gradually distributed compositions or structures. ...In recent years, metallic FGMs have been widely studied, and additive manufacturing (AM) has become an important approach to build metallic FGMs. This paper aims to provide an overview of the research progress in metallic FGMs fabricated by laser metal deposition (LMD), an AM process that is widely used in metallic materials. Firstly, the unique material properties and advantages of FGMs are introduced. Then, typical recent findings in transition path design, fabrication, and characterization for different types of metallic FGMs via LMD are summarized and discussed. Finally, challenges in fabricating metallic FGMs via LMD are discussed, and other related aspects in the area of FGMs such as model representation and numerical simulation are proposed for further investigation.
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In this study, a novel hybrid composite PCM was manufactured by adsorbing octadecane into the porous supporting material based on the aluminum nitride (AlN) material, which owned high thermal ...conductivity. Meanwhile, a layer of nanocapsule PCM was coated on its surface for increasing the latent heat and achieving the PCM encapsulation. The results showed that the AlN efficiently enhanced the thermal conductivity of the composite PCM, and the addition of nanocapsule PCM further improved the stability and latent heat of the composite PCM. The composite PCM melted at 26.12 °C with a latent heat of 116.26 kJ/kg and solidified at 25.02 °C with a latent heat of 115.96 kJ/kg. In addition, the leakage problem of pure PCM was solved, and the thermal conductivity of composite PCM was 3.5 W/(m·K), which was 17.5 times of pure PCM. More importantly, the dynamic thermal performance exhibited the composite PCM as an energy storage material for buildings was able to lower the fluctuation of building temperature in winter. Therefore, the as-prepared composite PCM is a desirable candidate for building energy storage systems.
•A novel thermal enhanced composite phase change material with aluminium nitride is developed.•The proposed composite is characterized by DSC for latent heat storage.•The thermal conductivity of proposed material is improved up to 3.5 W/(m·K).•Stability performance of the proposed compound is excellent with nanocapsules covered.
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By combining the waste of oil palm empty fruit bunch (EFB) and graphene oxide (GO), a GO/cellulose aerogel bio-nanocomposite was produced via a simple mixing method. The thermal properties of this ...nanocomposite were examined using thermogravimetric analysis (TGA), and the GO/cellulose aerogel bio-nanocomposite exhibited good thermal stability indicated by a delay in the degradation of the nanocomposite even at low GO incorporation. Experimental and modeled TGA curves were compared. The morphology of the GO/cellulose aerogel composite was observed under field emission scanning electron microscope. In GO/cellulose aerogel composite with 4 wt% GO, the pore volume and porosity decreased by more than 50% compared to aerogel without GO, and the density of the 4 wt% GO/cellulose aerogel composite showed a onefold increase compared with the pure cellulose aerogel. The degree of swelling and equilibrium-swelling ratio of regenerated GO/cellulose hydrogel and aerogel decreased with the higher GO concentration. The phase transition from EFB to regenerated GO/cellulose aerogel composite was evaluated using X-ray diffraction. This study has provided a simple pathway to produce environmentally friendly biocomposite materials.
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Flexible electrochemical energy storage (EES) devices such as lithium-ion batteries (LIBs) and supercapacitors (SCs) can be integrated into flexible electronics to provide power for portable and ...steady operations under continuous mechanical deformation. Ideally, flexible EES devices should simultaneously possess high flexibility, high energy density, and high power density, thus requiring appropriate electrode materials, electrolytes, and advanced structural designs of the electrodes. Generally, composite materials with specific components and unique structures have been widely investigated recently as flexible EES devices because these materials endow the devices with good bending, stretching, and compression capacity and are preferable to single-component materials. Thus, in this review work, we will give a detailed overview of the recent progress in composite electrode materials for flexible electrodes and composite electrolytes suitable for the development of flexible LIBs & SCs. We will special focus on the role of composite materials for applications in flexible EES devices of wearable electronics. We also give a brief introduction of structural designs to achieve flexibility and stretchablity in device/system levels. Finally, future perspectives and important research directions are highlighted and discussed.
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