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Characterization of Microwave Sintered Aluminium Composite Reinforced with Hydroxyapatite Extracted from Rihu Fish Scales

Venkatesh V.S.S., Prasad Kalapala, Deoghare Ashish B.

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

617--624

EN

In this study, Hydroxyapatite (HAp) is extracted from the Rihu fish scales which are generally dumped as garbage. The aluminium composite was fabricated through the powder metallurgy technique by reinforcing HAp (0, 5, 10 and 15 wt%) as a reinforcement. The fabricated samples were sintered through microwave sintering at 530℃ for 15 min under an argon gas environment. The fabricated composites were subjected to X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analysis to confirm the constituting elements and to describe the reinforcement dispersion in the matrix. Uniform reinforcement dispersion was observed for the composite reinforces with 5% HAp, 10% HAp particles. The mechanical characterization results reveal that the Al-10% HAp composite exhibits a microhardness value of 123 ± 3 Hv and maximum ultimate tensile strength of 263 ± 10 MPa and 299 ± 9 MPa compression strength was obtained due to the presence of a strong bond among the aluminium and HAp particles.

2

Health risk assessment in the vicinity of a copper smelter: particulate matter collected on a spider web

Trzyna Agnieszka, Rybak Justyna, Bartz Wojciech, Górka Maciej

Mineralogia

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2022

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Vol. 53, iss. 1

36--50

EN

We used spider webs as a particulate matter (PM) sampler to assess the possible health risk to the inhabitants of Legnica city (Poland). We aimed to find out if it is a useful material and could provide reliable information. We selected two spider families (Agelenidae and Linyphiidae) whose webs structure enhances the PM accumulation. The collected particles were analysed using a Scanning Electron Microscope equipped with Energy Dispersive X-Ray (SEM-EDX) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) which provided morphological and chemical information and allowed to indicate possible sources of pollution. The results showed that PM10, the fraction of particles smaller than 10 µm, was dominated by the particles of natural origin, while fine fractions were composed of diverse anthropogenic particles, whose origin can be connected with the activity of the copper smelter and in smaller quantity with the road traffic. The carcinogenic and non-carcinogenic health risk was assessed for these pathways: inhalation, ingestion, and dermal, for children and adults. The non-carcinogenic risk was very high (Hazard Index: HI > 1) both for children (Cu, Ni, Pb, Cd) and adults (Cu, As, Pb, Cd). Moreover, high carcinogenic risk (>10-4) was found in most of the sampling points. The study shows that spider webs are useful in biomonitoring of PM and can also be used for health risk assessment. In the studied region, it was found that the possible negative impact of air pollution on human health exists.

3

Scanning Electron Microscopy as a Tool for Castings Quality Analysis

Jezierski Jan, Dojka M., Stawarz M., Dojka R.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 1

53--61

EN

Nowadays, the best castings’ manufacturers have to meet very demanding requirements and specifications applicable to mechanical properties and other characteristics. To fulfill those requirements, more and more sophisticated methods are being used to analyze the internal quality of castings. In many cases, the commonly used Non-Destructive Methods, like X-ray or ultrasonic testing, are not enough to ensure precise and unequivocal evaluation. Especially, when the properties of the casting only slightly fail the specification and the reasons for such failures are very subtle, thus difficult to find without the modern techniques. The paper presents some aspects of such an approach with the use of Scanning Electron Microscopy (SEM) to analyze internal defects that can critically decrease the performance of castings. The paper presents the so-called bifilm defects in ductile and chromium cast iron, near-surface corrosion caused by sulfur, micro-shrinkage located under the risers, lustrous carbon precipitates, and other microstructure features. The method used to find them, the results of their analysis, and the possible causes of the defects are presented. The conclusions prove the SEM is now a powerful tool not only for scientists but it is more and more often present in the R&D departments of the foundries.

4

Microstructural Analysis of Concrete Using Cow Bone Ash for Alkali-Silica Reaction (ASR) Suppression

Adanikin Ariyo, Falade Funsho, Olutaiwo Adewale

Journal of Casting & Materials Engineering

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2020

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Vol. 4, no. 2

34--40

EN

Concrete pavements are prone to microstructural changes and deterioration when exposed to Alkali-Silica Reaction (ASR). ASR results in strength reduction, cracking, spalling and other defects in the concrete if left unchecked. Supplementary Cementitious Materials (SCMs) such as Cow Bone Ash (CBA) however can be used to improve concrete performance, hence its use in this study. Concrete samples were prepared at replacement levels of 0%, 5%, 10%, 15%, 20% and 30% of cement with Cow Bone Ash. The concrete samples were then subjected to petrographic and Scanning Electron Microscopy (SEM) analysis. Petrographic examination shows that the minimal and least amount of ASR gels and micro cracking were observed at 15% CBA replacement of cement in the concrete samples. Scanning Electron Microscopy (SEM) analysis shows that changes in the elemental composition of the concrete samples is related to the effect of CBA which enhances adhesion in the concrete. SEM analysis show that, in general, the change in microstructure in the concrete was mainly due to the change in the arrangement of the C-H-S compounds. The microstructure analysis indicates that CBA in concrete influences the densification of the concrete at the transition zone, resulting in a much lower porosity. This results in the concrete having a tightly bound layer that repels ingress of water and thereby inhibiting cracks and gel formation as water is a contributing factor to the ASR in concrete.

5

Effect of the Powder Consolidation Method Type on the Microstructure and Selected Properties of Al2O3-Cu-Ni Composite

Zygmuntowicz J., Wachowski M., Piotrkiewicz P., Kaszuwara W.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

967--974

EN

The present research is focused on the characterization of the composites from Al2O3-Cu-Ni system. Two methods of ceramic-metal composite forming were applied: uniaxial powder pressing and Pulse Plasma Sintering (PPS). To obtain the samples the powder mixtures containing 85 vol.% of Al2O3 and 15 vol.% of metal powders were used. Influence of the sintering process on microstructure and mechanical properties of the two series of the composites was analyzed in detail. The selected physical properties of samples were characterized by Archimedes immersion method. Vickers hardness and the fracture toughness of the composites was determined as well. The microstructure of the composites was characterized by XRD, SEM, EDX. Fractography investigation was carried out as well. Independently on composite production method Al2O3, Cu, Ni, and CuNi phases were revealed. Fractography investigation results revealed different character of fracture in dependence of fabrication method. Pulse Plasma Sintered samples were characterized by higher crack resistance and higher Vickers hardness in comparison to the specimens manufactured by uniaxial pressing.

6

Structural Aging and Degradation of Human Fingernail Plates Upon Cosmetic Agents

Kulesza S., Bramowicz M., Gwoździk M., Wilczyński S., Goździejewska A. M.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

181--184

EN

The knowledge whether and how chemical species react with tissues is important because of protection against harmful factors, diagnose of dermatological diseases, validation of dermatological procedures as well as effectiveness of topical therapies. In presented work the effects of chemical agents on plates of human fingernails were studied using Atomic Force Microscopy and Scanning Electron Microscopy. Apart from that, mapping of the elastic properties of the nails was also carried out. To obtain reliable measures of spatial evolution of the surface variations, recorded images were analyzed in terms of scaling invariance brought by fractal geometry, instead of common though not unique statistical measures.

7

Wpływ procesu redukcji na właściwości strukturalne i mechaniczne szkieł tlenkowych z grupy (Pb,Bi)-(Si,Ge)-O

Bochentyn B.

Technical Issues

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2015

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nr 2

3--8

EN

The effect of the reduction process in H2 at 380 °C on the microstructure and elemental composition of a glass Bi0.4Pb0.2Si0.4Ox has been investigated. It has been shown that after reduction a clearly separated top layer with a thickness of approx. 50 µm was formed on the surface of the sample. This layer is depleted of oxygen and has higher electrical conductivity than the interior of the glass. It has also been found that some granules of metallic bismuth with a diameter of tens to hundreds of nanometers were formed on the surface of the glass. Furthermore, depletion of lead was observed in these samples in relation to the initial stoichiometry of the glass prior to trial reduction.