Presence Of Metallic Component Research Articles

Fracture mechanical and ablation behaviors of C/SiC–Cu3Si–Cu interpenetrating composites and their dependence on metal addition and interface thickness

The C/SiC–Cu3Si–Cu interpenetrating composites were prepared by the ceramization and metallization of carbon fiber reinforced carbon aerogel (C/CA) preforms. Fracture mechanical and ablation behaviors as well as their dependence on metal addition and PyC interface thickness were investigated. With the presence of metallic components, the C/SiC–Cu3Si–Cu composites show pseudo-plastic fracture, typical brittle-plastic mixed fracture, and then ladder-like fracture with the PyC interface thickness increasing due to the co-existence of ductile and brittle components, obviously different from the fracture of conventional ceramic matrix composites. The composite with 3.0 μm-thick interface has the highest flexural strength of 292.8 MPa due to the proper interfacial bond strength and residual compressive stress. The composite with 1.9 μm-thick interface has the highest work of fracture but relatively low fracture toughness due to the abundant modes of crack propagation. The anti-ablation property is deteriorated with increased PyC thickness due to the weakened transpiration cooling effect and reduced oxide scale quality. The composite with 0.9 μm-thick interface exhibits lower mass and linear ablation rates of 0.054 mg cm−2 s−1 and 0.018 μm s−1 after ablation at 2200 °C for 600 s, respectively. This work provides vital insights into the control of the overall performance of carbon fiber reinforced ceramic-metal matrix composites.

Review of Metal-Resistant Structures for Radio Frequency Identification Tag Antennas

Amidst the rapid expansion of e-commerce and the consequential surge in industries such as transportation, logistics, and supply chain management, there has been remarkable growth. Radio Frequency Identification (RFID) technology, along with its associated tags, plays a pivotal role in the transmission and tracking of crucial information within these sectors. However, the presence of metallic components within RFID systems poses a significant obstacle to efficient antenna transmission. Consequently, there is a pressing need for the development of RFID tag antennas endowed with metal-resistant properties. This paper undertakes a comparative analysis of existing designs and structures for metal-resistant RFID tag antennas, providing valuable insights into their prospective developmental trajectories and potential applications. Such analysis serves as a pertinent reference for research and engineering endeavors across related domains.

Presence of metallic components in transdermal drug delivery systems and risk of skin burns

ObjectiveSkin burns are associated with the presence of metallic components in transdermal drug delivery systems during Magnetic Resonance Imaging, cardioversion, or defibrillation procedures.The aim of the study was to review the presence of metallic components in marketed products of transdermal drug delivery systems in Spain. MethodFor each pharmaceutical form, the summary of product characteristics was reviewed. If the information was not provided, manufacturers were contacted. ResultsWe identified 59 marketed products of transdermal drug delivery systems of 12 different active substances.59.3% of patches contained metallic components or their presence could not be ruled out. Information regarding the need to remove the patch was only included in 8 summaries of product characteristics (13.6%)A table was elaborated and included the following aspects: product, active substance, manufacturer, need to remove the patch before the exposure to magnetic or electric fields, and references. ConclusionMore than a half of the patches at the time of the study contained metals or their absence could not be confirmed by the manufacturer. However, this information was only included in 13.6% of summaries of product characteristics.

Magnetic Resonance Imaging of the Knee in the Presence of Bridging External Fixation: A Comparative Experimental Evaluation of Four External Fixators, Including Dolphix®.

Performing MR investigation on patients instrumented with external fixators is still controversial. The aim of this study is to evaluate the quality of MR imaging of the knee structures in the presence of bridging external fixators. Different cadaveric lower limbs were instrumented with the MR-conditional external fixators Hofmann III (Stryker, Kalamazoo, MI, USA), Large external Fixator (DePuy Synthes, Raynham, MA, USA), XtraFix (Zymmer, Warsaw, IN, USA) and a newer implant of Ketron Peek CA30 and ERGAL 7075 pins, Dolphix®, (Citieffe, Bologna, Italy). The specimens were MR scanned before and after the instrumentation. The images were subjectively judged by a pool of blinded radiologists and then quantitatively evaluated calculating signal intensity, signal to noise and contrast to noise in the five regions of interest. The area of distortion due to the presence of metallic pins was calculated. All the images were considered equally useful for diagnosis with no differences between devices (p > 0.05). Only few differences in the quantification of images have been detected between groups while the presence of metallic components was the main limit of the procedure. The mean length of the radius of the area of distortion of the pins were 53.17 ± 8.19 mm, 45.07 ± 4.33 mm, 17 ± 5.4 mm and 37.12 ± 10.17 mm per pins provided by Zimmer, Synthes, Citieffe and Stryker, respectively (p = 0.041). The implant of Ketron Peek CA30 and ERGAL 7075 pins showed the smallest distortion area.

Plastic litter from shotgun ammunition on Danish coastlines – Amounts and provenance

Plastic litter in the marine environment is a major global issue. Discarded plastic shotgun ammunition shells and discharged wads are an unwelcome addition and feature among the top ten litter items found on reference beaches in Denmark.To understand this problem, its scale and origins, collections were made by volunteers along Danish coastal shorelines. In all 3669 plastic ammunition items were collected at 68 sites along 44.6 km of shoreline. The collected items were scored for characteristic variables such as gauge and length, shot type, and the legibility of text, the erosion, and the presence of metallic components. Scores for characteristics were related to the site, area, and season and possible influences discussed.The prevalence of collected plastic shotgun litter ranges from zero to 41 items per 100 m with an average of 3.7 items per 100 m. Most ammunition litter on Danish coasts originates from hunting on Danish coastal waterbodies, but a small amount may come from further afield. North Sea coasts are the most distinctive suggesting the possible contribution of long distance drift as well as the likelihood that such litter can persist in marine habitats for decades.The pathway from initial discard to eventual wash-up and collection depends on the physical properties of plastic components, marine tides and currents, coastal topography and shoreline vegetation.Judging from the disintegration of the cartridge and the wear and decomposition of components, we conclude that there is a substantial supply of polluting plastic ammunition materials that has and will accumulate. These plastic items pose a hazard to marine ecosystems and wash up on coasts for many years to come. We recommend that responsible managers, hunters and ammunition manufacturers will take action now to reduce the problem and, thereby, protect ecosystems, wildlife and the sustainability of hunting.

Revisiting the He ii to H i ratio in the intergalactic medium

We estimate the He II to H I column density ratio, \eta = N(He II)/N(H I), in the intergalactic medium towards the high redshift (z_{em} = 2.885) bright quasar QSO HE 2347-4342 using Voigt-profile fitting of the H I transitions in the Lyman series and the He II Lyman-$\alpha$ transition as observed by the FUSE satellite. In agreement with previous studies, we find that $\eta > 50$ in most of the Lyman-$\alpha$ forest except in four regions where it is much smaller ($\eta \sim 10-20$) and therefore inconsistent with photo-ionization by the UV background flux. We detect O VI and C IV absorption lines associated with two of these regions ($z_{\rm abs}$ = 2.6346 and 2.6498). We show that if we constrain the fit of the H I and/or He II absorption profiles with the presence of metal components, we can accommodate $\eta$ values in the range 15-100 in these systems assuming broadening is intermediate between pure thermal and pure turbulent. While simple photo-ionization models reproduce the observed N(O VI)/N(C IV) ratio, they fail to produce low $\eta$ values contrary to models with high temperature (i.e T $\ge 10^5$ K). The Doppler parameters measured for different species suggest a multiphase nature of the absorbing regions. Therefore, if low $\eta$ values were to be confirmed, we would favor a multi-phase model in which most of the gas is at high temperature ($>$ 10$^5$ K) but the metals and in particular C IV are due to lower temperature ($\sim$ few $10^4$ K) photo-ionized gas.