Group Of Inorganic Materials Research Articles

Data fusion of laser-induced breakdown and Raman spectroscopies: Enhancing clay mineral identification

A straight-forward, data-driven approach for the reliable identification of clay minerals based on spectroscopy and multivariate analyses is presented here. No other group of inorganic materials have so many species, exhibit such a range of physicochemical properties, or enjoy a greater diversity of practical applications as the clay minerals. The emerging role of clays in a variety of pioneering disciplines, such as the pharmaceutical and astrobiological sciences, highlights their broad-ranging significance in natural science and engineering efforts. However, the highly variable chemical compositions and defect-rich structures of the clay minerals pose difficulties in their classification and identification. We introduce a new methodological approach which uses Raman and laser-induced breakdown spectroscopies (LIBS) to discriminate geological specimens based on their dominant clay mineralogy. Raman and LIBS provide complementary information about the molecular structure and elemental composition of an interrogated target, and, when considered simultaneously, contribute to a more comprehensive characterization of the system under study. What distinguishes this work from previous spectral investigations of clay mineralogy is the way in which the spectra are pre-processed and combined before analysis. Raman and LIBS data were collected from various clay-rich specimens and subsequently concatenated into a single data matrix to serve as a unique identifier of specimen composition – an approach known as low-level data fusion. Multivariate statistical analyses were used to identify mineralogical groups and to discriminate specimens based on their compositional similarities and differences. We evaluated the discrimination achieved by the fused data sets compared to that obtained by standalone use of Raman and LIBS data. Our results show that the use of data fusion strategies improved the discrimination model and allowed correct classification of all the samples based on their dominant clay mineralogy.

Implementation of a new thermal path within the structure of inorganic encapsulated power modules

The demands on power modules regarding power density and reliability are continuously rising. Conventional encapsulation materials are limited in their thermal performance. In this study, a completely new material class is used within a power module. This new class is the group of inorganic materials, specifically ceramic encapsulation materials. The use of ceramic encapsulation materials generates new possibilities for optimizing the heat dissipation within power modules. In comparison to conventional encapsulation materials, ceramic composites can dissipate the semiconductor's heat loss much more efficient due to its enhanced thermal conductivity. This improves the transient thermal resistance of the module (Zth). Furthermore, an additional copper layer (TMC - Thermal mass circuit), which is connected to the heatsink below, is applied to the top of the encapsulation. This opens up a new thermal path in the module without changing its footprint or overall structure. In particular, the geometrically difficult area above the on-chip contacts can be used completely for cooling for the first time. Experiments show that the combination of a ceramic encapsulation and the TMC structure can reduce the semiconductor's temperature by more than 12 K. This enables a higher lifetime, efficiency and reliability of power modules with high energy density.

Mordenite Nanorods Prepared by an Inexpensive Pyrrolidine‐based Mesoporogen for Alkane Hydroisomerization

AbstractThe front cover artwork for Issue 12/2019 is provided by researchers from the group of Inorganic Materials and Catalysis, Eindhoven University of Technology (The Netherlands). The image shows how a novel surfactant based on methylpiperidine modified by a hydrophobic tail (C16NMP) can downsize the synthesis of mordenite zeolite from massive crystals into more accessible nanorods. See the Full Paper itself at https://doi.org/10.1002/cctc.201900298.

Feasibility and strength properties of the geopolymeric binder made of fly ash suspension

Geopolymeric binders, or in general geopolymers, are nowadays applied in many different branches of the industry –also in building construction. This relatively new group of inorganic materials has similar strength properties as ordinary Portland cement (OPC) and in some features, it is even better (for example in terms of fire resistance or chemical resistance). It is also environmentally friendly material because industrial or mining tailings are used as its main components and the production process is not so energy consuming as in case of OPC. Paper presents laboratory research focusing on the curing temperature impact on strength properties of geopolymeric binder made of fly ash suspension. Besides the suspension which is a waste product from coal power plant, also recycled ground glass and metakaolin were used as the additions. The chemical activator of geopolimerisation reaction was prepared with the use of sodium hydroxide and sodium silicate. Prism samples 40x40x160 mm were done and then the flexural and compressive strength tests were performed. The paper also presents the impact of covering the moulds during heat curing on condition of geopolymeric binder samples.