Ion mobility spectrometry for monitoring high-purity oxygen

The ability of the ion mobility spectrometry (IMS) technique with a negative corona discharge (CD) ion source to detect trace amounts of impurities in high-purity O(2) has been explored. The processes of the formation of negative ions in negative CD IMS have been studied using the ion mobility spectrometry/mass spectrometry (IMS/MS) technique. The CD IMS and CD IMS/MS spectra of 5.0 and 6.0 oxygen with and without additional purification (CO(2) and H(2)O removal) have been measured. It has been proven that the trace amounts of N(2) in high-purity O(2) can be monitored using the CD IMS and/or CD IMS/MS technique.     

Mechanical Properties of Advanced Pore Morphology Foam Elements

Advanced pore morphology (APM) foam, consisting of sphere-like metallic foam elements, exhibits some particular mechanical properties with unique application possibilities. The article presents the results of experimental and computational testing of APM foam elements to determine their mechanical behavior under quasi-static and dynamic compressive loading conditions. Additionally, an infrared thermal imaging camera has been used during experimental testing. Evaluated mechanical properties give better insight into the behavior of single APM foam elements under different types of loading and provide a good base for further studies of the topology and morphology influence on the global behavior of composite structures, based on APM foam elements.     

Biodegradable zinc-based materials with a polymer coating designed for biomedical applications

Over the last decades, biodegradable metals have gained popularity for biomedical applications due to their ability to assist in tissue healing. These materials degrade in vivo, while the corrosion products formed are either absorbed or excreted by the body, and no further surgical intervention is required for removal. Intensive research has been carried out mainly on degradable biomaterials based on Mg and Fe. In recent years, zinc-based degradable biomaterials have been explored by the biomedical community for their intrinsic physiological relevance, desirable biocompatibility, intermediate degradation rate, tuneable mechanical properties and pro-regeneration properties. Since pure Zn does not exhibit sufficient mechanical properties for orthopedic applications, various Zn alloys with better properties are being developed. In this work, the combined effect of minor Fe addition to Zn and a polyethyleneglycol (PEG) coating on the surface morphology, degradation, cytotoxicity and mechanical properties of Zn-based materials was studied. There are several studies regarding the influence of the production of Zn alloys, but the effect of polymer coating on the properties of Zn-based materials has not been reported yet. A positive effect of Fe addition and polymer coating on the degradation rate and mechanical properties was observed. However, a reduction in biocompatibility was also detected.     

Germination of Phaseolus vulgaris L. Seeds after a Short Treatment with a Powerful RF Plasma

Seeds of common bean (Phaseolus vulgaris L.), of the Etna variety, were treated with low-pressure oxygen plasma sustained by an inductively coupled radiofrequency discharge in the H-mode for a few seconds. The high-intensity treatment improved seed health in regard to fungal contamination. Additionally, it increased the wettability of the bean seeds by altering surface chemistry, as established by X-ray photoelectron spectroscopy, and increasing surface roughness, as seen with a scanning electron microscope. The water contact angle at the seed surface dropped to immeasurably low values after a second of plasma treatment. Hydrophobic recovery within a month returned those values to no more than half of the original water contact angle, even for beans treated for the shortest time (0.5 s). Increased wettability resulted in accelerated water uptake. The treatment increased the bean radicle length, which is useful for seedling establishment in the field. These findings confirm that even a brief plasma treatment is a useful technique for the disinfection and stimulation of radicle growth. The technique is scalable to large systems due to the short treatment times.     

Impact of Copper-Doped Mesoporous Bioactive Glass Nanospheres on the Polymerisation Kinetics and Shrinkage Stress of Dental Resin Composites

We embedded copper-doped mesoporous bioactive glass nanospheres (Cu-MBGN) with antibacterial and ion-releasing properties into experimental dental composites and investigated the effect of Cu-MBGN on the polymerisation properties. We prepared seven composites with a BisGMA/TEGDMA (60/40) matrix and 65 wt.% total filler content, added Cu-MBGN or a combination of Cu-MBGN and silanised silica to the silanised barium glass base, and examined nine parameters: light transmittance, degree of conversion (DC), maximum polymerisation rate (R_max), time to reach R_max, linear shrinkage, shrinkage stress (PSS), maximum PSS rate, time to reach maximum PSS rate, and depth of cure. Cu-MBGN without silica accelerated polymerisation, reduced light transmission, and had the highest DC (58.8 ± 0.9%) and R_max (9.8 ± 0.2%/s), but lower shrinkage (3 ± 0.05%) and similar PSS (0.89 ± 0.07 MPa) versus the inert reference (0.83 ± 0.13 MPa). Combined Cu-MBGN and silica slowed the R_max and achieved a similar DC but resulted in higher shrinkage. However, using a combined 5 wt.% Cu-MBGN and silica, the PSS resembled that of the inert reference. The synergistic action of 5 wt.% Cu-MBGN and silanised silica in combination with silanised barium glass resulted in a material with the highest likelihood for dental applications in future.     

Design and analysis of an fMRI compatible haptic robot

Magnetic resonance (MR) compatible haptic devices have certain specific structural and operational properties, which are due to the magnetic field, and haptic requirements. Through the development of a haptic mechanism, which is compatible with a magnetic resonance environment, certain problems were solved, which are common to all robotic devices operating in an MR tunnel. This paper deals with the manipulability problem of a novel 3 DOF MR compatible haptic mechanism, considering limited space and its visualisation. An appropriate 3D visualisation method has been developed for analysing the manipulability characteristics of a haptic mechanism within an MR environment. Choosing a suitable driving system is one of the crucial design attributes for quality force transmission in haptic interfaces. This paper introduces certain adaptations, which have been done to enable the MR compatibility of a cable drive driven by an electric motor. It also presents the theoretical modelling of a cable drive for a 3 DOF MR compatible haptic mechanism, focusing on the hysteretic behaviour of polymeric cables.