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My comments concern the significant errors in the crystallographic part of the commented paper. [ABSTRACT FROM AUTHOR]

Abstract: Powders obtained from coal fly ash and paper mill sludge were milled alone or in mixture, pressed into specimens and sintered. Fired materials were characterized by density, water absorption, shrinkage on firing, crystal structure, microstructure, strength, hardness and toughness. Samples made with paper mill sludge alone had a high sintering temperature, contained extended fractures after sintering and were not further studied. All the other compositions, sintered between 1130 and 1190°C, showed low water absorption, density below 2.6g/cm3, fair mechanical properties and contained several phases. More in particular, the material containing 25wt% of coal ash and 75wt% of powder from paper sludge displayed the best overall behaviour. [Copyright &y& Elsevier]

Abstract: Glass-ceramics were prepared from mixtures of wastes generated from refining of silica sand and kaolin clay (Kira) and paper sludge ash. Kira and paper sludge ash were mixed in mass ratios of 55/45. The mixtures were melted at 1400°C and quenched in water to obtain glasses. The quenched glasses were ground to <48 mesh and used to prepare glass-ceramics. Crystallization of the parent glass occurred above 950°C, producing quartz solid solution at 1000°C and cristobalite at 1100°C as the major crystalline phases. The color of the glass-ceramics is white or slightly pale yellow. The four-point bending strengths of the as-fired glass-ceramics range from 63 to 66MPa and the Vickers microhardness values from 6.0 to 6.4GPa. The average linear thermal expansion coefficients of the glass-ceramics range from 6.3×10−6 /°C to 8.1×10−6 /°C (30–380°C) and show non-linearity around the phase transition temperatures of quartz and cristobalite. The chemical durability of the resulting glass-ceramics is excellent in alkali but poor in acid solution. The glass-ceramics show rather better performance than commercial glass-ceramics even when prepared solely from wastes starting materials. [Copyright &y& Elsevier]

Chemical vapor infiltration and reaction (CVI-R) is used to produce biomorphic high porous SiC ceramics based on biological structures such as paper. The paper fibers are first converted into a biocarbon (Cb) template by a carbonization step. In a second step methyltrichlorosilane (MTS) in excess of hydrogen is infiltrated into the Cb-template by CVI technique, depositing a Si/SiC layer around each fiber. The reaction (R) between biocarbon and excess silicon to form additional silicon carbide occurs during a subsequent thermal treatment as a third step of the ceramization process. Due to the mild infiltration conditions (850–900 °C) the initial micro- and macrostructure of the carbon preform is retained in the final ceramics. The applied characterization methods after every step of the ceramization process are X-ray Photoelectron Spectroscopy (XPS), Raman spectroscopy, Thermal Gravimetric Analysis (TGA), and Scanning Electron Microscopy (SEM). The bending strength of the resulting porous ceramics is measured by the double ring bending test. It is found that a slight excess of free Si in relation to the amount of carbon from the Cb-template must be deposited in the Si/SiC layer to achieve a nearly complete conversion of the Cb-templates into SiC ceramic. The weight gain after infiltration has to be at least 400 wt.%. Varying the infiltration conditions such as temperature, MTS concentration and infiltration time, ceramics in a wide range of porosity (55–80%) and mechanical properties (5–40 MPa) can be produced. A thermal treatment temperature of 1400 °C is found to be optimal for the reaction between the deposited Si and the biocarbon. [Copyright &y& Elsevier]

A biomorphic α-MoO3 ceramic was successfully derived from paper templates. By the infiltration of a Mo-contained solution into paper templates, followed by calcinations at 500°C in air, the cellulose fibers of paper were converted into branches composing of orthorhombic α-MoO3 crystals with grain size ranging from 0.5 to 2 μm. In the final product, the initial fibrous structure of the paper templates was retained. This simple biotemplate method provides a cost-effective and ecofriendly route to obtain advanced self-assembling biomorphic ceramics. [ABSTRACT FROM AUTHOR]

Chemical vapor infiltration (CVI) is used for producing biomorphic porous TiC ceramics derived from paper. The paper samples are first carbonized in inert atmosphere to yield biocarbon template structures (Cb-template). Subsequently, three routes for converting the Cb-templates into TiC ceramics are studied. The first route includes CVI with TiCl4-H2. The effect of methane as additional carbon source is investigated on the second route (TiCl4-H2-CH4). Finally, a two step CVI process (Route 3), first TiCl4-H2 and subsequent TiCl4-H2-CH4, is performed in order to improve both the grade of conversion of the Cb-template into TiC and the mechanical properties of the resulting porous TiC ceramics. Furthermore, porous TiO2 ceramics are produced by high temperature oxidation of the TiC ceramics in air flow. [Copyright &y& Elsevier]

Ceramics are used in hip implants and have been found to produce lower wear rates. This paper discusses the advantages and disadvantages of ceramics compared to other implant materials. Different types of ceramics that are being used are reviewed in terms of the wear characteristics, debris released, and their size together with other biological factors. In general, the wear rates in ceramics were lower than that of metal-on-metal and metal-on-polyethylene combinations. Results from several clinical studies are summarized in this paper providing full details from the published literature in this overview. [Copyright &y& Elsevier]

Development of ceramic pigments with controlled particle sizes below 1 µm is essential for the preparation of ceramic inks used in inkjet digital decoration that is currently being applied in the ceramics sector. A black ceramic pigment based on NiCoCrFe composition has been prepared using thermal decomposition of hydrotalcite-like compounds. The stoichiometry ratio between different cations was studied to obtain the blackest pigment, giving Ni0,5Co0,5CrFeO4 the better cation ratio, also the thermal treatment, comparing traditional firing in an electric furnace with microwave treatment. Samples have been characterized by X-ray diffraction, Scanning Electron Microscopy and Lab colour measurement. Microwave treatment showed the best way to obtain a pigment with spinel-type structure and a homogeneous size distribution near to 150 nm, with a high intensity and colorimetric data, reducing drastically the temperature and energy consumption to obtain a black ceramic pigment suitable to be utilized in digital ceramic inks. [ABSTRACT FROM AUTHOR]

• We visualized adhesive on a ceramic plate. • We visualized varnish on a printed paper. • We used near-infrared hyperspectral imaging at wavelengths of 1.0–2.35 µm. • We used correlation analysis, partial least squares regression analysis. • We also used linear discriminant analysis, decision tree, and KNN. We preliminarily examined whether it is possible to visualize synthetic materials applied to the surface of a base material by using near-infrared hyperspectral imaging at wavelengths of 1.0–2.35 µm. We focused on the applicability of this method for visualizing adhesives and varnishes, assessing the effect of underlying colorants on measurements, and selecting the optimal method for data analysis. Experimental samples were adhesive on a painted ceramic plate and varnish on printed paper. We performed correlation analysis, partial least squares regression analysis, linear discriminant analysis, decision tree, KNN and principal component scores 1 and 2 to evaluate the measurement data. The conventional method (visible/near-infrared spectroscopic/fluorescence photographs at wavelengths of 400–1000 nm.) could not visualize the adhesive on the painted ceramic plate or the varnish on the printed paper, whereas the new method could do so. Therefore, this method has the potential to be useful for inspecting the distribution of synthetic materials on the surface of a base material. [ABSTRACT FROM AUTHOR]

Historical overview of ceramic development has been provided in the paper. It has been stated that the trail of ceramics has been rooted in Indus valley civilization. Advancement of materials leads to afflux of development in the fields of science and technology. Present paper deals with the realm of Ceramic Engineering, mainly focuses on education and jobs in the respected fields in India. This paper also holds the framework and research work in Ceramic Engineering in India. It has been defined that the whole processing of ceramics is done in the laboratories, like refractories, ceramics white wares, fuel furnace and pyrometry etc. There are a number of jobs which are offered by government sector as well as private sector. It has been determined that ceramic engineers are able to get job opportunities in aerospace, automotive industry, building material manufacturing, chemical industries, electronics, food processing, mining, medicine and refinery sectors in India. Curricula, undergraduate and postgraduate programs in Ceramics Engineering have been characterized. The peculiarities of dual degree education in Ceramics Engineering have been described. It has been stated that there are several initiatives taken by the government for the enhancement of skills and knowledge in Ceramics Engineering, which have been discussed in the extant paper. It has been defined that a new advancement in Ceramics Engineering is the initiative for enhancement of the knowledge through video lectures, offered by a couple of institutes. The prospects of ceramics application have been analyzed. It has been stated that the momentousness of ceramics are protruding diurnally just like in sculptures designing, pottery, building constructions, sanitary & textile etc. Not only the designing field of ceramics but its use in electronics field has been covered. It has been concluded that ceramic has a great potential to give solutions to the heat absorption between the walls or contacting surfaces. Earthenware was the heretofore product of ceramics. It has been proved that the future scope of ceramic is enormous. It has also been stressed that nowadays Ceramic Engineering is one of the emerging fields in engineering education, but a very prospective one.