Editorial

4 pages, 182 KiB

Open AccessEditorial

Obtaining, Characterization and Applications of Advanced Materials

by Ion Sandu

Appl. Sci. 2023, 13(15), 8698; https://0-doi-org.brum.beds.ac.uk/10.3390/app13158698 - 27 Jul 2023

Cited by 2 | Viewed by 518

This special issue focused on scientific works in the field of obtaining, characterization and recent applications of advanced materials, protective films, nanomaterials with multiple uses, including medical, heritage artefact conservation science and civil and industrial engineering [...] Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

Research

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12 pages, 3410 KiB

Open AccessArticle

Ultra-Deep Oxidative Desulfurization of Fuel with H₂O₂ Catalyzed by Mesoporous Silica-Supported Molybdenum Oxide Modified by Ce

by Yang Chen, Qi Tian, Yongsheng Tian, Jiawei Cui and Guanghui Wang

Appl. Sci. 2021, 11(5), 2018; https://0-doi-org.brum.beds.ac.uk/10.3390/app11052018 - 25 Feb 2021

Cited by 10 | Viewed by 1855

Abstract

A mesoporous silica-supported molybdenum oxide catalyst with a cerium(Ce) modifier was prepared by in situ synthesis and used in a hydrogen peroxide (H₂O₂) system for the desulfurization of dibenzothiophene (DBT), benzothiophene (BT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) fuel oils. The catalytic [...] Read more.

A mesoporous silica-supported molybdenum oxide catalyst with a cerium(Ce) modifier was prepared by in situ synthesis and used in a hydrogen peroxide (H₂O₂) system for the desulfurization of dibenzothiophene (DBT), benzothiophene (BT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) fuel oils. The catalytic performance of the catalyst was studied. The catalyst was characterized by Fourier Transform Infra-Red (FT-IR), X-ray diffraction (XRD), Brunner−Emmet−Teller (BET), and X-ray Photoelectron Spectroscopy (XPS). The influences of m(catalyst)/m(fuel oil), v(H₂O₂)/v(fuel oil), reaction temperature, and reaction time were investigated. The catalyst had excellent catalytic oxidation desulfurization performance under moderate operational conditions. The catalytic performance was in the order DBT > 4,6-DMDBT > BT. The kinetic analysis results showed that the reaction was a pseudo first-order kinetics process and the apparent activation energies of DBT, BT, and 4,6-DMDBT were 46.67 kJ/mol, 56.23 kJ/mol, and 55.54 kJ/mol, respectively. The reaction products of DBT, BT, and 4,6-DMDBT were DBTO₂, BTO₂, and 4,6-DMDBTO₂, respectively. The recycling experiments indicated that DBT, BT, and 4,6-DMDBT removal could still reach levels of 94.0%, 63.0%, and 77.9% after five cycles. Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

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13 pages, 6756 KiB

Open AccessArticle

Improving Pressure–Velocity Limit of Mechanical Seal with Polycrystalline Diamond Coating

by Daidong Guo, Ningning Cai, Guoping Wu, Fangmin Xie, Shouhong Tan, Nan Jiang and He Li

Appl. Sci. 2020, 10(17), 6090; https://0-doi-org.brum.beds.ac.uk/10.3390/app10176090 - 02 Sep 2020

Cited by 9 | Viewed by 2433

Abstract

Polycrystalline diamond (PCD)-coated mechanical seal rings were prepared by hot filament chemical vapor deposition (HFCVD) on graphite-loaded silicon carbide (GSiC) substrates. From the initial deposition process, the diamond first nucleated and then grew into a dense coating with grain size of 4 μm [...] Read more.

Polycrystalline diamond (PCD)-coated mechanical seal rings were prepared by hot filament chemical vapor deposition (HFCVD) on graphite-loaded silicon carbide (GSiC) substrates. From the initial deposition process, the diamond first nucleated and then grew into a dense coating with grain size of 4 μm and thickness of 12.3 μm. The well-grown PCD coating, as confirmed by Raman spectroscopy and X-ray diffractometry, significantly improves the pressure–velocity limit of the mechanical seal applied in harsh operating conditions, no matter whether for a hard-to-soft mating combination or a hard-to-hard mating combination. Comparing GSiC against sintered silicon carbide (SSiC) combination (GSiC/SSiC), GSiC against graphite combination (GSiC/graphite) and PCD against graphite combination (PCD/graphite), PCD against SSiC combination (PCD/SSiC) shows the highest pressure velocity (PV) limit of 42.31 MPa·m/s with 4 kN loading at 4500 rpm rotation speed. An extremely low and stable friction coefficient and super mechanical properties under harsh conditions can be approved as the source of the high PV limit of PCD coating. A mechanical seal with PCD coating can be used for more demanding applications. Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

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14 pages, 3064 KiB

Open AccessArticle

Influence of TiO₂ Nanoparticles Addition on the Hydrophilicity of Cementitious Composites Surfaces

by Andreea Hegyi, Henriette Szilagyi, Elvira Grebenișan, Andrei Victor Sandu, Adrian-Victor Lăzărescu and Claudiu Romila

Appl. Sci. 2020, 10(13), 4501; https://0-doi-org.brum.beds.ac.uk/10.3390/app10134501 - 29 Jun 2020

Cited by 7 | Viewed by 2199

Abstract

The effect of the use of TiO₂ nanoparticles in the production of cementitious composites, worldwide already known, represents an area of interest for the development of materials with self-cleaning capacity; antimicrobial, antibacterial, antifungal properties; and to contribute to the reduction of environmental [...] Read more.

The effect of the use of TiO₂ nanoparticles in the production of cementitious composites, worldwide already known, represents an area of interest for the development of materials with self-cleaning capacity; antimicrobial, antibacterial, antifungal properties; and to contribute to the reduction of environmental pollution. This paper aims to analyze the influence that TiO₂ nanoparticles have on the cementitious matrix regarding hydrophilicity, this being one of the two main parameters of the self-cleaning mechanism. Experimental tests, conducted by using the indirect method of measuring the surface water absorption, indicated that an addition of 3%-6% (relative to the amount of cement) of TiO₂ nanoparticles is effective in terms of increasing the surface hydrophilicity of the cementitious composites. An excess of TiO₂ nanoparticles in the composite matrix (10% TiO₂ nanoparticles relative to the amount of cement) not only does not improve surface performance in terms of hydrophilicity, but also reduces them. However, in practice on a case-by-case basis, an analysis is required regarding the optimal amount of nanoparticles used as an addition in the mix-design of the cementitious materials that are intended to induce the quality of self-cleaning process, depending on the intended use, climate, degree and duration of sunlight, and so on. Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

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20 pages, 5993 KiB

Open AccessFeature PaperArticle

Authentication of a Painting by Nicolae Grigorescu Using Modern Multi-Analytical Methods

by Petru Ovidiu Tanasa, Ion Sandu, Viorica Vasilache, Ioan Gabriel Sandu, Ioan Cristinel Negru and Andrei Victor Sandu

Appl. Sci. 2020, 10(10), 3558; https://0-doi-org.brum.beds.ac.uk/10.3390/app10103558 - 21 May 2020

Cited by 11 | Viewed by 3191

Abstract

The paper presents the expertise of authenticating a painting by Nicolae Grigorescu through the involvement of multi-analytical techniques, in order to identify and evaluate some archaeometric and chemometric characteristics of the pictorial materials and of the support, used in determining the age. The [...] Read more.

The paper presents the expertise of authenticating a painting by Nicolae Grigorescu through the involvement of multi-analytical techniques, in order to identify and evaluate some archaeometric and chemometric characteristics of the pictorial materials and of the support, used in determining the age. The painting is made with oil colors on pressed cardboard, with preparation based on chalk powder and animal glue. The painting presents two elements as being counterfeit, which have attracted suspicions, namely the signature of the author (presenting a semi-transparent covering veil), and, on the back, a writing of dating, performed by a very controversial art historian. The investigation was carried out by direct analysis with magnification devices, in reflected UV (ultraviolet), VIS (visible), and NIR (near- infrared) light, and by OM, SEM-EDX, and μ-FTIR. The results showed that the painting is authentic and belongs to Nicolae Grigorescu, and the dating established previously by Amelia Pavel through the writing on the back is certain. Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

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14 pages, 4778 KiB

Open AccessArticle

Evaluation of the Corrosion Resistance of Phosphate Coatings Deposited on the Surface of the Carbon Steel Used for Carabiners Manufacturing

by Diana-Petronela Burduhos-Nergis, Petrica Vizureanu, Andrei Victor Sandu and Costica Bejinariu

Appl. Sci. 2020, 10(8), 2753; https://0-doi-org.brum.beds.ac.uk/10.3390/app10082753 - 16 Apr 2020

Cited by 34 | Viewed by 3830

Abstract

This study aims to evaluate the corrosion resistance of carbon steel, used for carabiners manufacturing, coated with three different types of phosphate layer. The phosphate layers have been obtained by phosphate conversion coating with three different types of phosphate solutions: zinc-based solution, zinc-iron-based [...] Read more.

This study aims to evaluate the corrosion resistance of carbon steel, used for carabiners manufacturing, coated with three different types of phosphate layer. The phosphate layers have been obtained by phosphate conversion coating with three different types of phosphate solutions: zinc-based solution, zinc-iron-based phosphate solution, and manganese-based phosphate solution. Additionally, the test was performed on zinc phosphate samples impregnated with molybdenum bisulfate-based oil and zinc phosphate samples further coated with a layer of elastomer-based paint. Considering the areas where the carabiners are used (civil engineering, navigation, oil industry, rescue operations, etc.), the corrosive environments studied are rainwater, Black Sea water, and fire extinguishing solution. The structure of the deposited layers was studied by scanning electron microscopy, while the interface structure between the alloy and corrosive environment was analyzed by electrochemical impedance spectroscopy. According to this study, the corrosion resistance of zinc-based phosphate coated samples and zinc/iron-based phosphate coated samples is higher than that of the studied carbon steel samples, despite the corrosion environment. Also, the most aggressive corrosion environment was the fire extinguishing solution. Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

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13 pages, 7586 KiB

Open AccessArticle

Mesoporous Carbon as Galvanic-Corrosion Activator Accelerates Fe Degradation

by Cijun Shuai, Yulong Li, Fang Deng, Youwen Yang, Shuping Peng, Fangwei Qi and Lida Shen

Appl. Sci. 2020, 10(7), 2487; https://0-doi-org.brum.beds.ac.uk/10.3390/app10072487 - 04 Apr 2020

Cited by 2 | Viewed by 1875

Abstract

Iron (Fe) has attracted intensive attention as a bone implant material because of its inherent biodegradability, favorable biocompatibility and mechanical properties. Nevertheless, it degrades too slowly in a physiological environment, which limits its further clinical application. In this work, mesoporous carbon (MC) was [...] Read more.

Iron (Fe) has attracted intensive attention as a bone implant material because of its inherent biodegradability, favorable biocompatibility and mechanical properties. Nevertheless, it degrades too slowly in a physiological environment, which limits its further clinical application. In this work, mesoporous carbon (MC) was introduced into Fe bone implant manufactured via a laser-additive manufacturing process. Particularly, MC possesses a noble standard corrosion potential and excellent electrical conductivity, thus acting as an effective cathode and activating micro-galvanic corrosion in the Fe matrix. More importantly, its high specific surface area enhanced the area ratio between cathode and anode, which further enhanced the galvanic corrosion effect. As a consequence, the corrosion rate was enhanced from 0.09 to 0.24 mm/year based on immersion tests. Besides, Fe/MC composite exhibited good cytocompatibility, as well as excellent mechanical properties. The positive results proved that the Fe/MC composite shows great potential as a bone implant. Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

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12 pages, 4235 KiB

Open AccessFeature PaperArticle

New Ecological Solutions Involved in the Cleaning of a 19th Century Icon

by Tudor Cosmin Iurcovschi, Viorica Vasilache, Ion Sandu, Marius Zaharia, Olga Pintilie and Andrei Victor Sandu

Appl. Sci. 2020, 10(3), 1175; https://0-doi-org.brum.beds.ac.uk/10.3390/app10031175 - 10 Feb 2020

Cited by 9 | Viewed by 2500

Abstract

Cleaning of old icons requires special attention to selecting the processes and systems compatible with the chemical nature and adhesions of the deposits, to not affect the polychrome layer or their conservation status. The study was carried out on a 19th century icon [...] Read more.

Cleaning of old icons requires special attention to selecting the processes and systems compatible with the chemical nature and adhesions of the deposits, to not affect the polychrome layer or their conservation status. The study was carried out on a 19th century icon made in fat tempera, on a thin layer of preparation that presents fouling. The cleaning was done using extracts obtained from sage, St. John’s Wort, and, respectively, licorice root teas obtained through different extraction processes: microwave, ultrasound, boiling, and room temperature, respectively. The washing capacity of the new system used was analyzed by analytical methods of assessing the cleaning degree: UV-Vis reflection, reflective colorimetry type CIE L*a*b*, co-assisted with optical microscopy and scanning electrone microscopy (SEM-EDX). Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

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Review

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28 pages, 1847 KiB

Open AccessReview

Selected Aspects Regarding the Restoration/Conservation of Traditional Wood and Masonry Building Materials: A Short Overview of the Last Decade Findings

by Radu Claudiu Fierascu, Mihaela Doni and Irina Fierascu

Appl. Sci. 2020, 10(3), 1164; https://0-doi-org.brum.beds.ac.uk/10.3390/app10031164 - 09 Feb 2020

Cited by 29 | Viewed by 6843

Abstract

Vernacular buildings are usually constructed using materials at hand, including wood, natural stone and bricks (either clay or mud bricks). All those materials are exposed to a series of environmental factors, affecting their structure and integrity. The literature review was conducted using different [...] Read more.

Vernacular buildings are usually constructed using materials at hand, including wood, natural stone and bricks (either clay or mud bricks). All those materials are exposed to a series of environmental factors, affecting their structure and integrity. The literature review was conducted using different databases (Scopus, Web of Science, ScienceDirect, SpringerLink) using as keywords the historical material, “heritage” and the terms regarding the desired effect, within the envisaged time period (2010–2019). The assessment of the results was performed by manual inspection (reading the entire article) and the selection of the works to be inserted in the current review was made by evaluating the contribution to the field. This review summarizes different aspects related to the restoration and conservation of wooden and masonry elements of traditional buildings, including materials used for biocidal interventions, protection against abiotic factors, cleaning and consolidation agents. Finally, a critical discussion regarding the current limitations and future perspectives concludes the review work, envisaging the role of researchers specialized in materials science in the context of cultural heritage conservation. Full article

(This article belongs to the Special Issue Obtaining, Characterization and Applications of Advanced Materials)

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