Different Classes Of Materials Research Articles

Design-experimental assessment of radiological hazards in residential and industrial premises

Construction of residential and industrial buildings is associated with a wide application of both traditional and new structural and finishing materials. Radiological conditions in buildings are determined radiation of natural radionuclides contained in structural and finishing materials of buildings. Mostly around the world national criteria are used governing the content of natural radionuclides in building materials, based on the recommendations of international regulatory bodies. In Russia in order to justify admissibility of structural and finishing building materials in housing construction people use experimental methods. In European Union countries government suggests calculating estimation for assessment of the applicability different materials in various areas of housing and civil construction. Earlier, the authors established the fact of possible inconsistencies between Russian and European standards in different classes of materials. In order to compare the applicability of different approaches were held complex researches including experimental determination content of natural radionuclides in materials, calculation of dose rate in specific rooms and direct measurements of dose rates. As basic model authors used approach applied in the European Union countries. Experimental studies were performed using methods scintillation spectrometry and radiometry. The objects of research were premises with bearing and enclosing concrete structures faced with tiles. Experimental dose rate values were determined after deduction of the radiation background on the terrain. The conducted studies showed that the application of the computational model with the use of experimental values of the activity of natural radionuclides leads in some cases to incorrect values of dose rate in the premises, which is associated with the accepted value of the radiation background. Despite the simplicity of the proposed approach and its direct use can lead to unreliable results. So the coincidence of the calculated and experimental data is irregular. Obtained results allow to make the main conclusion about the limited application of the estimated approach to evaluation of radiological hazard in living quarters. The most reliable are the experimental approach, despite its great labor intensity. Calculate approach should be applied at the preliminary stage of rejection of materials.

On the Common Origin of Structural Superplasticity in Different Classes of Materials

Abstract The present model starts with an assumption that grain/ interphase boundary sliding (GBS) that is dominant during optimal superplastic flow is slower than the accommodation processes of dislocation emission from sliding boundaries, highly localized diffusion in the boundary regions and/ or grain rotation that are present as a concomitant of the GBS process. When boundary sliding develops to a mesoscopic scale (of the order of a grain diameter or more), by the alignment of contiguous boundaries, plane interface formation/ mesoscopic boundary sliding is observed. Significant and simultaneous sliding along different plane interfaces and their interconnection can lead to large scale deformation and superplasticity. The accommodation steps, being faster than GBS, do not enter the strain rate equation. Mathematical development of these ideas using transition state theory results in a transcendental strain rate equation for steady state optimal superplastic flow, which when solved numerically helps one to describe the phenomenon quantitatively in terms of two constants, the activation energy for the rate controlling process, ΔF0and the threshold stress needed to be overcome for the commencement of mesoscopic boundary sliding, σ0.The analysis also explains quantitatively texture randomization as a function of superplastic strain. It is also pointed out, without going into details, that recently the problem has been reduced to FOUR “universal” constants, viz. the mean strain associated with a unit boundary sliding event g0, specific grain boundary energy γB, which is assumed to be isotropic, N the average number of boundaries that align to form a plane interface during mesoscopic boundary sliding and “a” a grain-size- and shape- dependent constant that obeys the condition 0 <a <0.5, in terms of which one can account for superplasticity in any material. In combination with the regression equations popularized by Frost and Ashby to predict the shear modulus of any material at any temperature, these four constants allow one to predict the steady state strain rate of any structurally superplastic material accurately, including those whose superplastic response is not considered for the analysis. The details of the last mentioned result, which are unpublished, will be presented elsewhere.

Cutting Materials in Half: A Graph Theory Approach for Generating Crystal Surfaces and Its Prediction of 2D Zeolites.

Scientific interest in two-dimensional (2D) materials, ranging from graphene and other single layer materials to atomically thin crystals, is quickly increasing for a large variety of technological applications. While in silico design approaches have made a large impact in the study of 3D crystals, algorithms designed to discover atomically thin 2D materials from their parent 3D materials are by comparison more sparse. We hypothesize that determining how to cut a 3D material in half (i.e., which Miller surface is formed) by severing a minimal number of bonds or a minimal amount of total bond energy per unit area can yield insight into preferred crystal faces. We answer this question by implementing a graph theory technique to mathematically formalize the enumeration of minimum cut surfaces of crystals. While the algorithm is generally applicable to different classes of materials, we focus on zeolitic materials due to their diverse structural topology and because 2D zeolites have promising catalytic and separation performance compared to their 3D counterparts. We report here a simple descriptor based only on structural information that predicts whether a zeolite is likely to be synthesizable in the 2D form and correctly identifies the expressed surface in known layered 2D zeolites. The discovery of this descriptor allows us to highlight other zeolites that may also be synthesized in the 2D form that have not been experimentally realized yet. Finally, our method is general since the mathematical formalism can be applied to find the minimum cut surfaces of other crystallographic materials such as metal–organic frameworks, covalent-organic frameworks, zeolitic-imidazolate frameworks, metal oxides, etc.

Magnetic and noncentrosymmetric Weyl fermion semimetals in the RAlGe family of compounds ( R=rareearth )

Weyl semimetals are novel topological conductors that host Weyl fermions as emergent quasiparticles. While the Weyl fermions in high-energy physics are strictly defined as the massless solution of the Dirac equation and uniquely fixed by Lorentz symmetry, there is no such constraint for a topological metal in general. Specifically, the Weyl quasiparticles can arise by breaking either the space-inversion ($\mathcal{I}$) or time-reversal ($\mathcal{T}$) symmetry. They can either respect Lorentz symmetry (type-I) or strongly violate it (type-II). To date, different types of Weyl fermions have been predicted to occur only in different classes of materials. In this paper, we present a significant materials breakthrough by identifying a large class of Weyl materials in the RAlX (R=Rare earth, Al, X=Ge, Si) family that can realize all different types of emergent Weyl fermions ($\mathcal{I}$-breaking, $\mathcal{T}$-breaking, type-I or type-II), depending on a suitable choice of the rare earth elements. Specifically, RAlX can be ferromagnetic, nonmagnetic or antiferromagnetic and the electronic band topology and topological nature of the Weyl fermions can be tuned. The unparalleled tunability and the large number of compounds make the RAlX family of compounds a unique Weyl semimetal class for exploring the wide-ranging topological phenomena associated with different types of emergent Weyl fermions in transport, spectroscopic and device-based experiments.

Silicon Nanomembranes with Hybrid Crystal Orientations and Strain States.

Methods to integrate different crystal orientations, strain states, and compositions of semiconductors in planar and preferably flexible configurations may enable nontraditional sensing-, stimulating-, or communication-device applications. We combine crystalline-silicon nanomembranes, patterning, membrane transfer, and epitaxial growth to demonstrate planar arrays of different orientations and strain states of Si in a single membrane, which is then readily transferable to other substrates, including flexible supports. As examples, regions of Si(001) and Si(110) or strained Si(110) are combined to form a multicomponent, single substrate with high-quality narrow interfaces. We perform extensive structural characterization of all interfaces and measure charge-carrier mobilities in different regions of a 2D quilt. The method is readily extendable to include varying compositions or different classes of materials.

Functional PEG Macromers for Biomedical Applications

Biomedical technology combines medicine and technology to diagnose, replace damaged site or regenerate tissue, and delivery of bioactive agent in a temporally controlled manner. Modified and unmodified natural and synthetic polymeric biomaterialsare currently formed in various structural shapes and chemical ingredients to overcome challenges. The recent developments in engineered PEG based hydrogel materials shows a great attractive research area due to its relatively high biocompatibility. The synthetic acrylated PEG or PEG-diacrylate and –multiacrylate monomers are the main backbone of photoinitiated radical polymerization of acrylates and polyesters used in non-degradable and degradable biomaterials. The physicochemical properties also enable to reinforce natural polymers structural characteristics. Recently published different classes of materials comprised of acrylated PEG macromers are summarized in this review.

Building Blocks for High Performance in Electrocatalytic CO2 Reduction: Materials, Optimization Strategies, and Device Engineering.

In recent years, screening of materials has yielded large gains in catalytic performance for the electroreduction of CO2. However, the diversity of approaches and a still immature mechanistic understanding make it challenging to assess the real potential of each concept. In addition, achieving high performance in CO2 (photo)electrolyzers requires not only favorable electrokinetics but also precise device engineering. In this Perspective, we analyze a broad set of literature reports to construct a set of design-performance maps that suggest patterns between performance figures and different classes of materials and optimization strategies. These maps facilitate the screening of different approaches to electrocatalyst design and the identification of promising avenues for future developments. At the device level, analysis of the network of limiting phenomena in (photo)electrochemical cells leads us to propose a straightforward performance metric based on the concepts of maximum energy efficiency and maximum product formation rate, enabling the comparison of different technologies.

Functional Microgels and Microgel Systems.

Microgels are macromolecular networks swollen by the solvent in which they are dissolved. They are unique systems that are distinctly different from common colloids, such as, e.g., rigid nanoparticles, flexible macromolecules, micelles, or vesicles. The size of the microgel networks is in the range of several micrometers down to nanometers (then sometimes called "nanogels"). In a collapsed state, they might resemble hard colloids but they can still contain significant amounts of solvent. When swollen, they are soft and have a fuzzy surface with dangling chains. The presence of cross-links provides structural integrity, in contrast to linear and (hyper)branched polymers. Obviously, the cross-linker content will allow control of whether microgels behave more "colloidal" or "macromolecular". The combination of being soft and porous while still having a stable structure through the cross-linked network allows for designing microgels that have the same total chemical composition, but different properties due to a different architecture. Microgels based, e.g., on two monomers but have either statistical spatial distribution, or a core-shell or hollow-two-shell morphology will display very different properties. Microgels provide the possibility to introduce chemical functionality at different positions. Combining architectural diversity and compartmentalization of reactive groups enables thus short-range coexistence of otherwise instable combinations of chemical reactivity. The open microgel structure is beneficial for uptake-release purposes of active substances. In addition, the openness allows site-selective integration of active functionalities like reactive groups, charges, or markers by postmodification processes. The unique ability of microgels to retain their colloidal stability and swelling degree both in water and in many organic solvents allows use of different chemistries for the modification of microgel structure. The capability of microgels to adjust both their shape and volume in response to external stimuli (e.g., temperature, ionic strength and composition, pH, electrochemical stimulus, pressure, light) provides the opportunity to reversibly tune their physicochemical properties. From a physics point of view, microgels are particularly intriguing and challenging, since their intraparticle properties are intimately linked to their interparticle behavior. Microgels, which reveal interface activity without necessarily being amphiphilic, develop even more complex behavior when located at fluid or solid interfaces: the sensitivity of microgels to various stimuli allows, e.g., the modulation of emulsion stability, adhesion, sensing, and filtration. Hence, we envision an ever-increasing relevance of microgels in these fields including biomedicine and process technology. In sum, microgels unite properties of very different classes of materials. Microgels can be based on very different (bio)macromolecules such as, e.g., polysaccharides, peptides, or DNA, as well as on synthetic polymers. This Account focuses on synthetic microgels (mainly based on acrylamides); however, the general, fundamental features of microgels are independent of the chemical nature of the building moieties. Microgels allow combining features of chemical functionality, structural integrity, macromolecular architecture, adaptivity, permeability, and deformability in a unique way to include the "best" of the colloidal, polymeric, and surfactant worlds. This will open the door for novel applications in very different fields such as, e.g., in sensors, catalysis, and separation technology.

Effective elastic properties of two dimensional multiplanar hexagonal nanostructures

A generalized analytical approach is presented to derive closed-form formulae for the elastic moduli of hexagonal multiplanar nano-structures. Hexagonal nano-structural forms are common for various materials. Four different classes of materials (single layer) from a structural point of view are proposed to demonstrate the validity and prospective application of the developed formulae. For example, graphene, an allotrope of carbon, consists of only carbon atoms to form a honeycomb like hexagonal lattice in a single plane, while hexagonal boron nitride (hBN) consists of boron and nitrogen atoms to form the hexagonal lattice in a single plane. Unlike graphene and hBN, there are plenty of other materials with hexagonal nano-structures that have the atoms placed in multiple planes such as stanene (consists of only Sn atoms) and molybdenum disulfide (consists of two different atoms: Mo and S). The physics based high-fidelity analytical model developed in this article are capable of obtaining the elastic properties in a computationally efficient manner for wide range of such materials with hexagonal nano-structures that are broadly classified in four classes from structural viewpoint. Results are provided for materials belonging to all the four classes, wherein a good agreement between the elastic moduli obtained using the proposed formulae and available scientific literature is observed.

The Interface of an Intrinsic Hybrid Composite – Development, Production and Characterisation

Due to a combination of different classes of materials, intrinsic hybrid composites are characterised by high strength and low weight. The mechanical properties of hybrid parts are mainly determined by the interface between the different materials. Consequently, this interface has to be considered in detail within the development of an intrinsic hybrid composite. The general approach of the considered composite is the combination of a mechanical form fit with adhesive bonding. This contribution focuses on the development, production and characterisation of the interface between aluminium and a fibre reinforced polymer as well as of the hybrid composite.

Local Physicomechanical Properties of Materials for Use in Calibration of Nanoindentation Instruments

Studies of variations in the hardness of representative materials of different classes over broad ranges of loads and depths of indentation are carried out. The usability of these materials is demonstrated and boundaries on the ranges of use of hardness meters produced from these materials for calibration of nanoindentation instruments are established.

Radiation effects across classes of materials

physica status solidi (a)Volume 213, Issue 11 p. 2959-2959 PrefaceFree Access Radiation effects across classes of materials First published: 15 November 2016 https://doi.org/10.1002/pssa.201670677AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL The Advances in Materials & Processing Technologies Conference, AMPT 2015, took place at the Carlos III University in Leganés, Madrid (Spain), from December 14–17, 2015. This conference series started in 1993 and it is held every two years with multiple parallel sessions covering a broad range of topics related to advances in materials engineering. This year, and for the first time in this conference series, there was a symposium devoted to radiation effects of materials: Characterization and Modelling of radiation effects across classes of materials. The goal of this symposium was to shed light on the physical mechanisms driving the change of properties due to irradiation in different classes of materials, from those used in nuclear applications to those of interest to the semiconductor industry, highlighting commonalities and differences. The symposium was very successful, with 41 oral presentations from 11 different countries. We want to thank all the participants and specially the keynote presenters that introduced the different topics discussed in this symposium: Cristelle Pareige (CNRS/GPM), Enrique Martínez (LANL), Antonio Rivera (UPM), Matthias Krack (PSI), Catherine Sabathier (CEA/DEN/ DEC), Frederic Mazen (CEA/LETI), Marta Serrano (CIEMAT), Michael Fluss (LLNL), Fernando Agullo- Lopez (UAM) and Kai Nordlund (UH). The topics covered included both experimental results and modelling in the area of radiation effects in different materials. Reflecting the current interest in this field, most of the talks were devoted to nuclear materials, both structural materials, mainly tungsten and iron based alloys, and nuclear fuels. Other topics discussed were the effect of irradiation in semiconductor materials, particularly silicon and the effect of radiation in complex materials such as high-entropy alloys. One common feature in this symposium was the importance of modelling in the understanding and development of materials. In this Special Section of physica status solidi (a) a representation of some of the topics covered in this symposium is presented, starting with a Feature Article on radiation effects in oxides 1 and followed by contributions on modelling microstructure evolution with object kinetic Monte Carlo in iron-based alloys 2-5, understanding point defects in silicon carbide 6 and modeling aluminum alloys 7. Guest Editors Ignacio Martin-Bragado, Lorenzo Malerba, María José Caturla, and Marjorie Bertolus References 1 F. Agulló-López, A. Climent-Font, A. Muñoz-Martin, and A. Zucchiatti, Phys. Status Solidi A. 213 (11), 2960 (2016), this issue. 2 M. J. Aliaga, I. Dopico, I. Martin-Bragado, and M. J. Caturla, Phys. Status Solidi A. 213 (11), 2969 (2016), this issue. 3 L. Messina, M. Chiapetto, P. Olsson, C. S. Becquart, and L. Malerba, Phys. Status Solidi A. 213 (11), 2974 (2016), this issue. 4 M. Chiapetto, L. Malerba, A. Puype, and C. S. Becquart, Phys. Status Solidi A. 213 (11), 2981 (2016), this issue. 5 M. J. Konstantinović, W. Van Renterghem, M. Matijašević, B. Minov, M. Lambrecht, T. Toyama, M. Chiapetto, and L. Malerba, Phys. Status Solidi A. 213 (11), 2988 (2016), this issue. 6 G. Roma, Phys. Status Solidi A. 213 (11), 2995 (2016), this issue. 7 S. I. Choi, G.-G. Lee, J. Kwon, and J. H. Kim, Phys. Status Solidi A. 213 (11), 3000 (2016), this issue. Volume213, Issue11November 2016Pages 2959-2959 ReferencesRelatedInformation

Multiple elastic scattering of electrons in condensed matter

Since the 1940s, much attention has been devoted to the problem of accurate theoretical description of electron transport in condensed matter. The needed information for describing different aspects of the electron transport is the angular distribution of electron directions after multiple elastic collisions. This distribution can be expanded into a series of Legendre polynomials with coefficients, Al. In the present work, a database of these coefficients for all elements up to uranium (Z=92) and a dense grid of electron energies varying from 50 to 5000 eV has been created. The database makes possible the following applications: (i) accurate interpolation of coefficients Al for any element and any energy from the above range, (ii) fast calculations of the differential and total elastic-scattering cross sections, (iii) determination of the angular distribution of directions after multiple collisions, (iv) calculations of the probability of elastic backscattering from solids, and (v) calculations of the calibration curves for determination of the inelastic mean free paths of electrons. The last two applications provide data with comparable accuracy to Monte Carlo simulations, yet the running time is decreased by several orders of magnitude. All of the above applications are implemented in the Fortran program MULTI_SCATT. Numerous illustrative runs of this program are described. Despite a relatively large volume of the database of coefficients Al, the program MULTI_SCATT can be readily run on personal computers. Program summaryProgram title: MULTI_SCATTProgram Files doi:http://dx.doi.org/10.17632/cvt9yz9gj8.1Licensing provisions: GNU General Public License 3 (GPL)Programming language: Fortran 90Nature of problem: Typically, elastic electron backscattering probabilities are estimated from results of Monte Carlo simulations of electron trajectories in a solid. This approach, although very convenient for a programmer, has major drawbacks: (i) the solid acceptance angles of analyzers are rather small, thus a large number of electron trajectories must be generated to obtain reasonable statistics; (ii) large running times are needed to reach an acceptable precision; (iii) results are always burdened with a statistical error. In the program MULTI_SCATT, an analytical formalism is implemented which leads to an accuracy comparable with Monte Carlo simulations, however it is faster by several orders of magnitude.Solution method: The program MULTI_SCATT requires presence of the database containing the coefficients Al for the series expansion of the differential elastic-scattering cross section. This database has a large volume of 96.2 Mb; a major computer effort is needed to complete these. This database has a large volume of 96.2 Mb; a major computer effort is needed to complete these calculations, and it has been decided to avoid this stage by providing the precalculated Al data. To obtain the Al value for a selected energy, the data from the database are interpolated in logarithmic coordinates. The elastic electron scattering probability is calculated from a slowly convergent series. Acceleration of the series convergence was found to be effective in the considered range of electron energies. Consequently, the running times of the program MULTI_SCATT are considerably decreased.Additional comments:(i) Restrictions: The program MULTI_SCATT can be used for electron energies between 100 and 5000 eV. Calculations of the elastic-backscattering probability and the calibration curve are performed under the assumption of normal incidence of the primary beam. This program is designed for applications in elemental solids, however, it can also be generalized to compounds (see text).(ii) Unusual features: To facilitate the use of the program MULTI_SCATT, several additional databases of parameters needed for the calculations are implemented using the DATA statement: inelastic mean free paths for different classes of materials, number of electrons in the valence band, atomic masses, densities, etc.Running time: Depending on the option selected, the running time is typically of the order of tens of milliseconds. For example, for tungsten and an electron energy of 500 eV, the running time varies from 12.8 milliseconds (angular distribution of electron directions after two collisions) to 60.2 milliseconds (calibration curve).

(Invited) Exploiting Luminescence for Measurements of Temperature

Temperature is by far the most-measured physical quantity, and temperature sensors are used by a large extent in daily life, industry, military, medicine, etc., with a market share of about 75%–80% of all sensors. Demands for temperature measurements of moving or contact sensitive objects, difficult to access bodies, objects in hazardous locations, at the nanoscale, in living organisms and cells, have stimulated research on the development of new temperature measurement concepts and temperature probes. Luminescence thermometry is among aspiring concepts capable of meeting aforementioned demands in the future. The changes of luminescence properties of materials with temperature allows some materials to act as sensitive thermometers. The phenomenon become the basis of a new arm in the field of luminescence spectroscopy commonly termed as a luminescence thermometry. This lecture will present a brief introduction into the concept of temperature measurements via luminescence, with the description of the temperature quenching of emission. Then, an overview of different concept modalities of luminescence thermometry will be given including: the steady-state luminescence concepts (use of the emission band shapes and positions, emission intensity and intensity ratios, use of the materials with a single- or multi- emission centers) and concepts based on the temporal changes in emission (emission decay- and rise-times). The most important quantities used to characterize the performance of a measurements (such as temperature sensitivities, temperature and spatial resolution, measurement ranges) will be explained and compared between different measurements modalities as well as between different classes of materials utilized as temperature probes. Finally, several designs of temperature sensing by luminescence in a different application fields will be highlighted.

ChemInform Abstract: Layer Like Porous Materials with Hierarchical Structure

AbstractReview: 324 refs.

Introduction to inaugural issue from PIAM

Progress in Additive Manufacturing has been initiated and inspired due to a crescent demand from both industrial and scientific communities to jointly contribute with their new achievements and applied results in the different areas of these technologies. As an interdisciplinary area, AM interconnects concepts from material science, simulation, manufacturing, tooling and design in a broad field of applications. Although each of these areas are well represented by highly scored journals, which can figure as platform for publication of their achievements, Progress in Additive Manufacturing urge to unite scientific and industrial papers, reviews and short communications within the scope of one single journal. One singular aspect from AM is related with the velocity with which AM technologies have been inserted in industry, laboratories and research centers. Nowadays, it can be certainly expected to find a ‘‘3D printer’’ in almost every technological laboratory in every major manufacturing industry or research group worldwide. AM technologies have been accepted and then implemented prior to any other aspect of the technology development. The design rules, or better the freedom in design rules, have been pushing designers over their borders. Material scientists are being forced to understand that material can be manipulated locally or layer-by-layer to achieve new properties and that the opportunities to create graded materials are extended. Even the industry has implemented AM technologies prior to their standards and are urging now for that, therefore quality assurance are examined to address industry demands/requirements. By facing the fact that AM is pushing us beyond the conventional boundaries of science and technology, we have agreed to create PIAM as platform for all unconventional and re-created aspects of material science, manufacturing, tooling, design, simulation and standardization. We are very glad that PIAM has been well accepted by the scientific and industrial communities. The first issue in a double edition, just reinforces this fact. In the first edition, the three different classes of materials have been explored, metals, ceramics and polymers. Also the most wide-spread AM technologies are present, powder bed fusion, material extrusion and material jetting. The articles increase the understanding of the correlation and dependency between materials, processes and part quality. They comprehend aspects of the process chain qualification and material characteristics especially for the powder bed technology and the material extrusion and jetting. Additionally the design is shown as an important tool for the use of AM particularly for production. The relevance of the additive technologies for industrial processes is described on background of traditional casting and hybrid manufacturing. The investigations present current developments of technologies and the optimization of processes e.g. by parameter modeling and indicate an important view on the research activities and also on industrial utilization of AM. As editors, we are very thankful for the support of all colleagues and contributors. To the authors, representing the research community all over the world, we really appreciate their work and cooperation to generate an interesting journal on a high scientific level! & Cynthia Wirth cynthia.wirth@siemens.com

Dynamics of the formation of laser-induced periodic surface structures (LIPSS) upon femtosecond two-color double-pulse irradiation of metals, semiconductors, and dielectrics

In order to address the dynamics and physical mechanisms of LIPSS formation for three different classes of materials (metals, semiconductors, and dielectrics), two-color double-fs-pulse experiments were performed on Titanium, Silicon and Fused Silica. For that purpose a Mach–Zehnder interferometer generated polarization controlled (parallel or cross-polarized) double-pulse sequences at 400nm and 800nm wavelength, with inter-pulse delays up to a few picoseconds. Multiple of these two-color double-pulse sequences were collinearly focused by a spherical mirror to the sample surfaces. The fluence of each individual pulse (400nm and 800nm) was always kept below its respective ablation threshold and only the joint action of both pulses lead to the formation of LIPSS. Their resulting characteristics (periods, areas) were analyzed by scanning electron microscopy. The periods along with the LIPSS orientation allow a clear identification of the pulse which dominates the energy coupling to the material. For strong absorbing materials (Silicon, Titanium), a wavelength-dependent plasmonic mechanism can explain the delay-dependence of the LIPSS. In contrast, for dielectrics (Fused Silica) the first pulse always dominates the energy deposition and LIPSS orientation, supporting a non-plasmonic formation scenario. For all materials, these two-color experiments confirm the importance of the ultrafast energy deposition stage for LIPSS formation.

ЭКСПЕРЕМЕНТАЛЬНОЕ ОБОСНОВАНИЕ ВЫБОРА ПЛОМБИРОВОЧНОГО МАТЕРИАЛА ПРИ ЛЕЧЕНИИ КАРИЕСА КОРНЯ

<p>High prevalence of root caries and high frequency of defects fit the seals makes the problem of filling materials choice for treatment root caries relevant. To justify the treatment of root caries by optimizing the choice of filling material. For our study, when filling cavities, the most commonly used filling materials of different classes, were chosen: nanohybrid composite with an adhesive system, triple curing hybrid glass ionomer cement, packable self-curing high strength glass ionomer cement. In experiment, marginal permeability of studied materials towards hard tissue (enamel, dentin, and root cement) were assessed on a five-point system Khera S.C, Chan K.C. 45 sampleswas investigated in total (for 15 samples in each group).</p>

Preface to the 50th anniversary issue of the Journal of Materials Science

In his book ‘‘The Coming of Materials Science’’ [1], the late Professor Robert Wolfgang Cahn FRS documented the rise of Materials Science as a distinct discipline from its roots in solid-state physics, metallurgy, polymer chemistry, inorganic chemistry, mineralogy, glass, and ceramic technology. The development of the discipline was a process in which he was intimately involved from 1942 when he enrolled at Trinity College, Cambridge to read Metallurgy, to his death from leukemia in 2007. His technical contributions were remarkably diverse, spanning such areas as: defects and deformation mechanisms, crystal growth, recrystallization, intermetallic compounds, and metallic glasses. It was these broad interests that led him to become such a staunch advocate for Materials Science as a discipline. Another of his passions was scientific editing, and he is remembered as much for his editing of several major journals and books as he is for his scientific research work. In 1964, Robert Cahn was invited by the publishers Chapman and Hall to establish the Journal of Materials Science as the first broad-spectrum Materials Science journal. As Chairman of Editors, he recruited a group of Editors with complementary areas of expertise, gave them independent powers of decision on submitted papers, and encouraged them to be pro-active in soliciting papers from key researchers on novel topics. This helped to ensure that the journal fulfilled its mission of being a broad-spectrum inclusive periodical that brought together work on different classes of materials using a wide variety of different experimental and theoretical approaches. The first issue appeared in April of 1966, and the Journal grew rapidly over the next few years to become a major international forum for research in Materials Science. In Robert Cahn’s memoirs [2], he said that the years he devoted to creating the Journal of Materials Science represented his single most important editorial contribution to the field. Over the last five decades, there have been many changes to the Journal, to the community that it serves, and to the field as a whole. The publishers have undergone several re-organizations and changes of ownership, and are now part of the Springer Nature group. Specialist sister journals have been spun off in the areas of Materials in Electronics and Materials in Medicine, while others such as Interface Science have been incorporated into the main journal. The community has broadened to encompass more biologists, chemists, and physicists due to developments in, for example, tissue engineering, nanostructured catalysts, and functional oxides, respectively. There have also been dramatic changes in the synthesis, processing, characterization, and computational modeling techniques available to materials scientists, and these advances have had a revolutionary effect on research directions in the field. Throughout, the Editors have maintained an open and flexible definition of Materials Science so that the Journal remains true to Robert Cahn’s original vision of a broadspectrum publication. This has been helped by stability in the leadership of the Journal with just four Chairmen/ Editors-in-Chief over the first 50 years: Professors Robert Cahn, William Bonfield, Rees Rawlings, and since 2004, C. Barry Carter. In 2006, the 40th anniversary of the founding of the Journal was marked with a special issue (volume 41, issue 3) comprising reviews, original research articles, and commentaries written by current and former Editors. The & Mark Aindow m.aindow@uconn.edu

Development Trends in Porous Adsorbents for Carbon Capture.

Accumulation of greenhouse gases especially CO2 in the atmosphere leading to global warming with undesirable climate changes has been a serious global concern. Major power generation in the world is from coal based power plants. Carbon capture through pre- and post- combustion technologies with various technical options like adsorption, absorption, membrane separations, and chemical looping combustion with and without oxygen uncoupling have received considerable attention of researchers, environmentalists and the stake holders. Carbon capture from flue gases can be achieved with micro and meso porous adsorbents. This review covers carbonaceous (organic and metal organic frameworks) and noncarbonaceous (inorganic) porous adsorbents for CO2 adsorption at different process conditions and pore sizes. Focus is also given to noncarbonaceous micro and meso porous adsorbents in chemical looping combustion involving insitu CO2 capture at high temperature (>400 °C). Adsorption mechanisms, material characteristics, and synthesis methods are discussed. Attention is given to isosteric heats and characterization techniques. The options to enhance the techno-economic viability of carbon capture techniques by integrating with CO2 utilization to produce industrially important chemicals like ammonia and urea are analyzed. From the reader's perspective, for different classes of materials, each section has been summarized in the form of tables or figures to get a quick glance of the developments.