The field of cantilever-based sensing emerged in the mid-1990s and is today a well-known technology for label-free sensing which holds promise as a technique for cheap, portable, sensitive and highly parallel analysis systems. The research in sensor realization as well as sensor applications has increased significantly over the past 10 years. In this review we will present the basic modes of operation in cantilever-like micromechanical sensors and discuss optical and electrical means for signal transduction. The fundamental processes for realizing miniaturized cantilevers are described with focus on silicon- and polymer-based technologies. Examples of recent sensor applications are given covering such diverse fields as drug discovery, food diagnostics, material characterizations and explosives detection.

http://iopscience.iop.org/article/10.1088/0034-4885/74/3/036101/pdf

Cantilever-like micromechanical sensors

The impact-induced deposition of Al13 clusters with icosahedral structure on Ni(0 0 1) surface was studied by molecular dynamics (MD) simulation using Finnis–Sinclair potentials. The incident kinetic energy (Ein) ranged from 0.01 to 30 eV per atom. The structural and dynamical properties of Al clusters on Ni surfaces were found to be strongly dependent on the impact energy. At much lower energy, the Al cluster deposited on the surface as a bulk molecule. However, the original icosahedral structure was transformed to the fcc-like one due to the interaction and the structure mismatch between the Al cluster and Ni surface. With increasing the impinging energy, the cluster was deformed severely when it contacted the substrate, and then broken up due to dense collision cascade. The cluster atoms spread on the surface at last. When the impact energy was higher than 11 eV, the defects, such as Al substitutions and Ni ejections, were observed. The simulation indicated that there exists an optimum energy range, which is suitable for Al epitaxial growth in layer by layer. In addition, at higher impinging energy, the atomic exchange between Al and Ni atoms will be favourable to surface alloying.

Nuclear instruments and methods in physics research section B : beam interactions with materials and atoms

Optimization of selective laser melting parameters and influence of post heat treatment on microstructure and mechanical properties of maraging steel

Carbon nanomaterials against pathogens; the antimicrobial activity of carbon nanotubes, graphene/graphene oxide, fullerenes, and their nanocomposites.

In last few years, properties of titanate nanotubes were extensively studied due to their potential applications in solar cells, electronics, chemical sensors, (photo)catalysis, hydrogen sensing and as mesoporos material for ion exchange. Titanate nanotubes are especially interesting because of their high aspect ratio and high specific surface area. Although there are some ambiguities regarding the exact structure and chemical composition of titanate nanotubes, it is generally accepted that the nanotubes have a layered titanate structure. An interlayer space of about 8 A ; is occupied by water molecules and alkali metal cations. However, the mechanism of nanotube formation and growth are still the subject of the numerous studies. In this work the formation of titanate nanotubes are discussed in the view of different TiO2 precursors. The thermal stability of prepared nanutubes have been studied in situ at high temperatures. The influence of Na+ content on the thermal stability of titanate nanotubes is also considered in details. Titanate nanotubes were sinthesized by hydrothermaly treating the TiO2 powder with NaOH solution. The starting precursors for nanotube synthesis were anatase or the mixture of anatase, rutile, and high-pressure TiO2II phase (TiO2-II) as a major component. The samples with various Na/Ti ratios were prepared by ion-exchange of interlayer Na+ cations with H+ ions under controlled pH conditions. The structural changes in the nanotubes induced by the thermal treatment were studied in situ by Raman spectroscopy (RS) and transmission electron microscopy (TEM). The morphology and the microstructure of the nanotubes before and after the thermal treatment in heating stage for RS were additionally examined by TEM and selected area electron diffraction (SAED). We found that hydrothermal treatment of mixture of TiO2 phases (anatase, rutile, and TiO2-II) leads to the formation of titanate nanotubes with structure and morphology similar to the nanotubes obtained from pure anatase, as observed both by RS and TEM. However, the temperature stability of nanotubes prepared from mixtures containing TiO2-II was much lower. These nanotubes undergo phase transition to anatase at temperatures lower than 100 °C, while, in the case of nanotubes obtained from anatase precursor, Raman bands characteristic for titanate nanotubes were visible up to 300 o ; C. At 500 o ; C titanate nanotubes in H-form were copletely transformed to anatase. Furthermore, titanate nanotubes in Na-form showed even better thermal stability – tubular structure was preserved to the temperatures as high as 500 °C. Phase transformation temperatures observed for nanotubes prepared from anatase are in good agreement with X-ray diffraction results reported by E. Morgano Jr. et al. [1]. [1] E. Morgado Jr., M. A. S. de Abreu, O. R. C. Pravia, B. A. Marinkovic, P. M. Jardim, F. C. Rizzo, A. S. Araujo, Solid State Sciences 8 (2006) 888.

High temperature Raman spectroscopy of titanate nanotubes

In this paper, flexural strength, fs, of cold isostatically pressed (CIP) high purity alumina ceramics was determined by the three-point bend test. It was found that flexural strength shows a large variation and can be described by a two-parameter Weibull distribution function, with the scale parameter 0, and the Weibull modulus m. These parameters were determined by the linear regression using the measured values of fs. It was found that the measured flexural strength, fs, of alumina ceramics follows the Weibull distribution. The flexural strength values were found to range from 266.7 to 357.5 MPa.

Flexural strength of alumina ceramics: weibull analysis

Advances in food packages are oriented to obtain improved quality and safety. Incorporation of antimicrobial compounds in the form of nano-fillers into polymer-based food packaging materials has received considerable attention. These active packages are applied to extend shelf life while maintaining nutrition quality and ensuring microbiological safety. Antimicrobial nanocomposite films are desirable for application in the food industry due to their advantages: structural integrity and barrier properties imparted by the matrix, as well as the antimicrobial properties resulting from impregnated antimicrobial agents. Metal nanoparticles, metal oxide nanomaterials, and carbon nanotubes are mostly used in developing antimicrobially active polymer materials. This chapter deals with some of the most important questions related to metallic nanoparticles in food packaging (health and environmental considerations, performance, and costs), with the special emphasize on their applicable and toxicological properties.

Metal nanoparticles and carbon nanotubes—perfect antimicrobial nano-fillers in polymer-based food packaging materials

With Additive Manufacturing - AM it is possible to create physical models, prototypes, components, tools and functional parts from 3D data constructed using the computer (CAD), with complicated geometry, which is very difficult or even impossible to do with other manufacturing technologies. AM processes for the manufacturing of prototypes use metals, ceramics and polymers in the form of liquids, powders, wire, foil, etc. However, there are many limitations, primarily in the selection of materials. Therefore, it is necessary to know the material properties, and how the various parameters of the machine influence on them, especially if it is manufacturing functional parts. The paper provides a brief overview of Selective Laser Sintering – SLS, and how the machine parameters (layer thickness, speed and power of laser) influence the mechanical properties of materials (tensile properties and hardness).

Influence of laser sintering parameters on mechanical properties of polymer products

The effect of cross-linking on the dynamics of amorphous poly(vinyl cinnamate) (PVCN) below and above the glass transition temperature (Tg) was studied by means of mechanical spectroscopy. The polymer is cross-linked by irradiating it with ultraviolet light, and it is controlled by the irradiation time, where the kinetics is observed by means of Fourier transform infrared spectroscopy. The evolving links between molecules hinder molecular mobility and thus influence the mechanical loss in the material, leading to (i) a shift of Tg to higher temperatures, (ii) a substantial decrease of the strength of the corresponding α-relaxation, (iii) an increase of Young's modulus, and (iv) an increased damping of PVCN below the glass transition.

Mechanical spectroscopy of PVCN with increasing cross-linking degree

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Tatjana Haramina

Papers

Flexural strength of alumina ceramics: weibull analysis

Metal nanoparticles and carbon nanotubes—perfect antimicrobial nano-fillers in polymer-based food packaging materials

Influence of laser sintering parameters on mechanical properties of polymer products

Mechanical spectroscopy of PVCN with increasing cross-linking degree

Debdatta Ratna: Epoxy Composites: Impact Resistance and Flame Retardancy