Production and characterization of hydrogen-reduced submicron tungsten powders—Part 1: State of the art in research, production and characterization of raw materials and tungsten powders

Author(s):  
W.D Schubert ◽  
E Lassner
1992 ◽  
Vol 00 (8) ◽  
pp. 4-4 ◽  
Author(s):  
Eric A. Draper ◽  
Jan Skalny

The need for continued rehabilitation of our concrete infrastructure has lead to the adaptation of modern “state-of-the-art” analytical methods for the characterization of concrete and other cementitious materials. Some of these techniques have not, until relatively recently, been commonly associated with the evaluation of concrete but are very useful both as tools for quality assurance and in the determination of the extent of existing damage. The technique of interest here is the coordinated electron-optical microscopic evaluation of concrete.Concrete is the most widely used building material in the world. Contrary to popular belief, concrete is not inert but chemically very complex and dynamic. While it is true that, pound for pound, concrete and its raw materials (cement, aggregate and water} are the most inexpensive building materials available for construction, it is also true that it responds to its environment in numerous and sometimes very subtle ways. These responses may sometimes result in a loss of durability and tremendous amounts of time and money being expended while searching for the cause(s) of the problem and providing a cost-effect solution A quick survey of any large metropolitan area and the on-going construction repairs to highways and bridge decks there will quickly confirm this.


1992 ◽  
Vol 00 (8) ◽  
pp. 11-14
Author(s):  
Eric A. Draper ◽  
Jan Skalny

The need for continued rehabilitation of our concrete infrastructure has lead to the adaptation of modern “state-of-the-art” analytical methods for the characterization of concrete and other cementitious materials. Some of these techniques have not, until relatively recently, been commonly associated with the evaluation of concrete but are very useful both as tools for quality assurance and in the determination of the extent of existing damage. The technique of interest here is the coordinated electron-optical microscopic evaluation of concrete.Concrete is the most widely used building material in the world. Contrary to popular belief, concrete is not inert but chemically very complex and dynamic. While it is true that, pound far pound, concrete and its raw materials (cement, aggregate and water) are the most inexpensive building materials available for construction, it is also true that it responds to its environment in numerous and sometimes very subtle ways. These responses may sometimes result in a loss of durability and tremendous amounts of time and money being expended while searching far the cause(s) of the problem and providing a cost-effect solution. A quick survey of any large metropolitan area and the on-going construction repairs to highways and bridge decks there will quickly confirm this.


Author(s):  
Wolfgang Albrecht ◽  
Juergen Moers ◽  
Bernd Hermanns

The Helmholtz Nano Facility (HNF) is a state-of-the-art cleanroom facility. The cleanroom has ~1100 m2 with cleanroom classes of DIN ISO 1-3. HNF operates according to VDI DIN 2083, Good Manufacturing Practice (GMP) and aquivalent to Semiconductor Industry Association (SIA) standards. HNF is a user facility of Forschungszentrum Jülich and comprises a network of facilities, processes and systems for research, production and characterization of micro- and nanostructures. HNF meets the basic supply of micro- and nanostructures for nanoelectronics, fluidics. micromechanics, biology, neutron and energy science, etc..The task of HNF is rapid progress in nanostructures and their technology, offering efficient access to infrastructure and equipment. HNF gives access to expertise and provides resources in production, synthesis, characterization and integration of structures, devices and circuits. HNF covers the range from basic research to application oriented research facilitating a broad variety of different materials and different sample sizes.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3564
Author(s):  
Arnas Majumder ◽  
Laura Canale ◽  
Costantino Carlo Mastino ◽  
Antonio Pacitto ◽  
Andrea Frattolillo ◽  
...  

The building sector is known to have a significant environmental impact, considering that it is the largest contributor to global greenhouse gas emissions of around 36% and is also responsible for about 40% of global energy consumption. Of this, about 50% takes place during the building operational phase, while around 10–20% is consumed in materials manufacturing, transport and building construction, maintenance, and demolition. Increasing the necessity of reducing the environmental impact of buildings has led to enhancing not only the thermal performances of building materials, but also the environmental sustainability of their production chains and waste prevention. As a consequence, novel thermo-insulating building materials or products have been developed by using both locally produced natural and waste/recycled materials that are able to provide good thermal performances while also having a lower environmental impact. In this context, the aim of this work is to provide a detailed analysis for the thermal characterization of recycled materials for building insulation. To this end, the thermal behavior of different materials representing industrial residual or wastes collected or recycled using Sardinian zero-km locally available raw materials was investigated, namely: (1) plasters with recycled materials; (2) plasters with natural fibers; and (3) building insulation materials with natural fibers. Results indicate that the investigated materials were able to improve not only the energy performances but also the environmental comfort in both new and in existing buildings. In particular, plasters and mortars with recycled materials and with natural fibers showed, respectively, values of thermal conductivity (at 20 °C) lower than 0.475 and 0.272 W/(m⋅K), while that of building materials with natural fibers was always lower than 0.162 W/(m⋅K) with lower values for compounds with recycled materials (0.107 W/(m⋅K)). Further developments are underway to analyze the mechanical properties of these materials.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4312
Author(s):  
Marzena Smol

Circular economy (CE) is an economic model, in which raw materials remain in circulation as long as possible and the generation of waste is minimized. In the fertilizer sector, waste rich in nutrients should be directed to agriculture purposes. This paper presents an analysis of recommended directions for the use of nutrient-rich waste in fertilizer sector and an evaluation of possible interest in this kind of fertilizer by a selected group of end-users (nurseries). The scope of research includes the state-of-the-art analysis on circular aspects and recommended directions in the CE implementation in the fertilizer sector (with focus on sewage-based waste), and survey analysis on the potential interest of nurseries in the use of waste-based fertilizers in Poland. There are more and more recommendations for the use of waste for agriculture purposes at European and national levels. The waste-based products have to meet certain requirements in order to put such products on the marker. Nurserymen are interested in contributing to the process of transformation towards the CE model in Poland; however, they are not fully convinced due to a lack of experience in the use of waste-based products and a lack of social acceptance and health risk in this regard. Further actions to build the social acceptance of waste-based fertilizers, and the education of end-users themselves in their application is required.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1411
Author(s):  
José Luis P. Calle ◽  
Marta Ferreiro-González ◽  
Ana Ruiz-Rodríguez ◽  
Gerardo F. Barbero ◽  
José Á. Álvarez ◽  
...  

Sherry wine vinegar is a Spanish gourmet product under Protected Designation of Origin (PDO). Before a vinegar can be labeled as Sherry vinegar, the product must meet certain requirements as established by its PDO, which, in this case, means that it has been produced following the traditional solera and criadera ageing system. The quality of the vinegar is determined by many factors such as the raw material, the acetification process or the aging system. For this reason, mainly producers, but also consumers, would benefit from the employment of effective analytical tools that allow precisely determining the origin and quality of vinegar. In the present study, a total of 48 Sherry vinegar samples manufactured from three different starting wines (Palomino Fino, Moscatel, and Pedro Ximénez wine) were analyzed by Fourier-transform infrared (FT-IR) spectroscopy. The spectroscopic data were combined with unsupervised exploratory techniques such as hierarchical cluster analysis (HCA) and principal component analysis (PCA), as well as other nonparametric supervised techniques, namely, support vector machine (SVM) and random forest (RF), for the characterization of the samples. The HCA and PCA results present a clear grouping trend of the vinegar samples according to their raw materials. SVM in combination with leave-one-out cross-validation (LOOCV) successfully classified 100% of the samples, according to the type of wine used for their production. The RF method allowed selecting the most important variables to develop the characteristic fingerprint (“spectralprint”) of the vinegar samples according to their starting wine. Furthermore, the RF model reached 100% accuracy for both LOOCV and out-of-bag (OOB) sets.


Geosciences ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 36
Author(s):  
Vayia Xanthopoulou ◽  
Ioannis Iliopoulos ◽  
Ioannis Liritzis

The present study deals with the characterization of a ceramic assemblage from the Late Mycenaean (Late Helladic III) settlement of Kastrouli, at Desfina near Delphi, Central Greece using various analytical techniques. Kastrouli is located in a strategic position supervising the Mesokampos plateau and the entire peninsula and is related to other nearby coeval settlements. In total 40 ceramic sherds and 8 clay raw materials were analyzed through mineralogical, petrographic and microstructural techniques. Experimental briquettes (DS) made from clayey raw materials collected in the vicinity of Kastrouli, were fired under temperatures (900 and 1050 °C) in oxidizing conditions for comparison with the ancient ceramics. The petrographic analysis performed on thin sections prepared from the sherds has permitted the identification of six main fabric groups and a couple of loners. The aplastic inclusions recognized in all fabric groups but one confirmed the local provenance since they are related to the local geology. Fresh fractures of representative sherds were further examined under a scanning electron microscope (SEM/EDS) helping us to classify them into calcareous (CaO > 6%) and non-calcareous (CaO < 6%) samples (low and high calcium was noted in earlier pXRF data). Here, the ceramic sherds with broad calcium separation are explored on a one-to-one comparison on the basis of detailed mineralogical microstructure. Moreover, their microstructure was studied, aiming to estimate their vitrification stage. The mineralogy of all studied samples was determined by means of X-ray powder diffraction (XRPD), permitting us to test the validity of the firing temperatures revealed by the SEM analysis. The results obtained through the various analytical techniques employed are jointly assessed in order to reveal potters’ technological choices.


Cosmetics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 62
Author(s):  
Giovanni Tafuro ◽  
Alessia Costantini ◽  
Giovanni Baratto ◽  
Stefano Francescato ◽  
Laura Busata ◽  
...  

As public attention on sustainability is increasing, the use of polysaccharides as rheological modifiers in skin-care products is becoming the first choice. Polysaccharide associations can be used to increase the spreading properties of products and to optimize their sensorial profile. Since the choice of natural raw materials for cosmetics is wide, instrumental methodologies are useful for formulators to easily characterize the materials and to create mixtures with specific applicative properties. In this work, we performed rheological and texture analyses on samples formulated with binary and ternary associations of polysaccharides to investigate their structural and mechanical features as a function of the concentration ratios. The rheological measurements were conducted under continuous and oscillatory flow conditions using a rotational rheometer. An immersion/de-immersion test conducted with a texture analyzer allowed us to measure some textural parameters. Sclerotium gum and iota-carrageenan imparted high viscosity, elasticity, and firmness in the system; carob gum and pectin influenced the viscoelastic properties and determined high adhesiveness and cohesiveness. The results indicated that these natural polymers combined in appropriate ratios can provide a wide range of different textures and that the use of these two complementary techniques represents a valid pre-screening tool for the formulation of green products.


Sign in / Sign up

Export Citation Format

Share Document