NON-CRACKING TECHNIQUES FOR GROUTING

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Miroslav Todorov
Keyword(s):  
Economic Effect ◽  
Inorganic Materials ◽  
Small Scale ◽  
Deep Foundations ◽  
High Porosity ◽  
Structure And Properties ◽  
Waste Products ◽  
Natural Materials ◽  
Colloidal Clay ◽  
Materials Used

Techniques for improving the ground base have been used since ancient times. The need of the geotechnical engineer to use zones with weak (cracked or high porosity) soil poses new, increasingly complicated problems. The solutions must consider requirements for the materials used and restrictions over the invasion. The use of natural (inorganic) materials is an approach resulting from the low speed of the change of the properties. The insignificant effect of the environment on the properties of the materials to be grouted is unquestionable. Here we should consider a number of factors connected with the anthropogenic conditions. An important aspect in the choice of materials is the expected positive changes in the structure and properties of the natural materials-improvement of soil skeleton structure, preservation of the migration of water, filling saturation, decreasing the consolidation deformability and others. The use of techniques for grouting with relatively small influence over the structure and properties of the natural materials requires certain basic mechanical parameters. Here we should pay attention to the scale of the interventions as a whole, the effect of which is considerably smaller than in usual techniques for different deep foundations. Another important aspect of these techniques is the economic effect, which creates conditions for a number of optimizations concerning the use of small-scale resources, by-products (colloidal clay, flay ash, lime, gypsum), small quantities of waste products, short periods for realization and others.

Current Highlights About the Safety of Inorganic Nanomaterials in Healthcare

2019 ◽  
Vol 26 (12) ◽  
pp. 2147-2165 ◽  
Author(s):  
Luana Perioli ◽  
Cinzia Pagano ◽  
Maria Rachele Ceccarini
Keyword(s):  
Zinc Oxide ◽  
Inorganic Material ◽  
Small Dimension ◽  
Inorganic Materials ◽  
Intracellular Space ◽  
Increased Risk ◽  
Inorganic Nanomaterials ◽  
Materials Used ◽  
Health Field ◽  
Fundamental Requirement

: In recent years inorganic materials are largely present in products intended for health care. Literature gives many examples of inorganic materials used in many healthcare products, mainly in pharmaceutical field. : Silver, zinc oxide, titanium oxide, iron oxide, gold, mesoporous silica, hydrotalcite-like compound and nanoclays are the most common inorganic materials used in nanosized form for different applications in the health field. Generally, these materials are employed to realize formulations for systemic use, often with the aim to perform a specific targeting to the pathological site. The nanometric dimensions are often preferred to obtain the cellular internalization when the target is localized in the intracellular space. : Some materials are frequently used in topical formulations as rheological agents, adsorbents, mattifying agents, physical sunscreen (e.g. zinc oxide, titanium dioxide), and others. : Recent studies highlighted that the use of nanosized inorganic materials can represent a risk for health. The very small dimension (nanometric) until a few years ago represented a fundamental requirement; however, it is currently held responsible for the inorganic material toxicity. This aspect is very important to be considered as actually numerous inorganic materials can be found in many products available in the market, often dedicated to infants and children. These materials are used without taking into account their dimensional properties with increased risk for the user/patient. : This review deals with a deep analysis of current researches documenting the toxicity of nanometric inorganic materials especially those largely used in products available in the market.

scholarly journals A multi-analytical approach for the characterisation of the oldest pictorial cycle in the 12th century monastery Santa Maria delle Cerrate

2013 ◽  
Vol 1 (1) ◽  
pp. 12 ◽  
Author(s):  
Giuseppe E. De Benedetto ◽  
Amedeo Savino ◽  
Daniela Fico ◽  
Daniela Rizzo ◽  
Antonio Pennetta ◽  
...  
Keyword(s):  
Analytical Approach ◽  
Point Of View ◽  
Inorganic Materials ◽  
Multidisciplinary Research ◽  
South Italy ◽  
Material Characterisation ◽  
12Th Century ◽  
Materials Used ◽  
The University ◽  
Santa Maria

A multidisciplinary research, currently in progress at the University of Salento in collaboration with the Lecce Provincial Museum, interests different artistic expressions widespread in the Salento peninsula (South Italy). In the present study, the characterisation of organic and inorganic materials used in the oldest pictorial cycle found in the 12th century monastery Santa Maria delle Cerrate was carried out thanks to a multi-analytical approach. Previous investigations have focused on the problem of dating the frescoes mainly on the basis of the stylistic aspects and the material characterisation has been definitely underinvestigated. Chromatographic and spectrometric techniques were used: micro-Raman spectroscopy was used for recognising pigments and gas chromatography with mass spectrometric detection for analysing organic binders. These techniques enabled us to characterise pigments and binders. The presence of both true fresco and tempera bound pigments was assessed. Among the different pigments detected, the results relevant to the blue paints were interesting: two different blue pigments were, indeed, identified, lapis lazuli and smalt (cobalt blue glass) both unexpected. As a result, Santa Maria delle Cerrate appears to be the first known example of their use in South Italy. From a conservation point of view, moreover, the knowledge of the palette permitted to highlight the reason of observed decay of some paints: for instance, lead white was used in some panels, explaining their blackening.

scholarly journals Early-Age Thermal-Shrinkage Cracking in Deep Foundations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Łukasz Grabowski ◽  
Monika Mitew-Czajewska
Keyword(s):  
Thermal Shrinkage ◽  
Future Research ◽  
Early Age ◽  
Deep Foundations ◽  
Shrinkage Cracking ◽  
The United Kingdom ◽  
Normative Requirements ◽  
Geotechnical Design ◽  
European Standards ◽  
Materials Used

Abstract With the growing rate of urbanisation, deep foundations are playing an ever-larger role in the development of cities, reaching deeper than before to fulfil the requirements of new constructions. While current European standards include design procedures for structural and geotechnical design, they lack provisions for massive deep foundations with regard to early-age thermal effects. This paper presents aspects of the phenomenon especially important for deep foundations and discusses normative requirements that influence their thermal behaviour. Further, the paper describes the methods and results of the research carried out in the United Kingdom on 1.50-m-thick diaphragm walls of a deep circular shaft. Shaft features are described, as well as the materials used. The measurements were carried out using vibrating wire strain gauges coupled with temperature readings. The results presented refer to one of the test panels concreted in January 2020. The temperature results are analysed together with the influence of work scheduling on the readings. Strain results that indicate contractive behaviour of the test panel are investigated together with the possible causes leading to such readings. Plans and directions for future research are discussed.

Polymer Solar Cells

2012 ◽  
pp. 101-119
Author(s):  
Catalin Zaharia
Keyword(s):  
Solar Cells ◽  
Polymer Solar Cells ◽  
Inorganic Materials ◽  
Major Drawback ◽  
Environmentally Safe ◽  
Large Production ◽  
Materials Used ◽  
Solar Cell Technology ◽  
Significant Attention ◽  
Plastic Solar Cell

Currently, the active materials used for the fabrication of solar cells are mainly inorganic. Materials such as silicon (Si), gallium-arsenide (GaAs), cadmium-telluride (CdTe), and cadmium-indium-selenide (CIS). Nevertheless, the large production cost for the silicon solar cells is one of the major drawback in this field. This chapter is dedicated to a critical presentation of another type of photovoltaics, called polymer, or plastic, solar cell technology. Polymer solar cells have attracted significant attention in the past few years due to their potential of providing environmentally safe, lightweight, flexible, and efficient solar cells.

Ultra-low density aerogel optical applications

1993 ◽  
Vol 8 (2) ◽  
pp. 352-355 ◽  
Author(s):  
S.P. Hotaling
Keyword(s):  
Surface Topology ◽  
Low Density ◽  
High Porosity ◽  
Fractal Surface ◽  
Surface Geometry ◽  
Surface Machining ◽  
Low Weight ◽  
Optical Applications ◽  
Materials Used ◽  
Reflective Coatings

Despite the extremely low density and the hence low weight of aerogel materials, the applicability of these materials to reflective applications has had little attention due to the high porosities exhibited by the materials. This high porosity yields an intrinsically rough but uniform surface topology for aerogel of density in the low hundreds of milligrams per cubic centimeter and a fractal surface geometry for lower density aerogel (densities of the order of tens of milligrams per cubic centimeter). This paper presents new results of aerogel materials used as ultra-light substrates for reflective coatings by way of surface machining, polishing, and planarization prior to metallization, and the optical characterization thereof.

scholarly journals Materials and Applications for Low-Cost Ceramic Membranes

Membranes ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 105 ◽  
Author(s):  
Amanmyrat Abdullayev ◽  
Maged Bekheet ◽  
Dorian Hanaor ◽  
Aleksander Gurlo
Keyword(s):  
Water Treatment ◽  
Raw Materials ◽  
Low Cost ◽  
Temperature Stability ◽  
Ceramic Membranes ◽  
Production Costs ◽  
High Temperature Stability ◽  
Waste Products ◽  
Recent Developments ◽  
Materials Used

In water treatment applications, the use of ceramic membranes is associated with numerous advantages relative to polymer-based filtration systems. High-temperature stability, fouling resistance, and low maintenance requirements contribute to lower lifecycle costs in such systems. However, the high production costs of most commercially available ceramic membranes, stemming from raw materials and processing, are uneconomical for such systems in most water treatment applications. For this reason, there is a growing demand for new ceramic membranes based on low-cost raw materials and processes. The use of unrefined mineral feedstocks, clays, cement, sands, and ash as the basis for the fabrication of ceramic membranes offers a promising pathway towards the obtainment of effective filtration systems that can be economically implemented in large volumes. The design of effective ceramic filtration membranes based on low-cost raw materials and energy-efficient processes requires a balance of pore structure, mass flow, and robustness, all of which are highly dependent on the composition of materials used, the inclusion of various pore-forming and binding additives, and the thermal treatments to which membranes are subjected. In this review, we present recent developments in materials and processes for the fabrication of low-cost membranes from unrefined raw materials, including clays, zeolites, apatite, waste products, including fly ash and rice husk ash, and cement. We examine multiple aspects of materials design and address the challenges relating to their further development.

Aerogel for Microsystems Thermal Insulation: System Design and Process Development

2005 ◽  
Author(s):  
Brian Smith ◽  
David Romero ◽  
Damena Agonafer ◽  
Jason Gu ◽  
Cristina H. Amon
Keyword(s):  
Thermal Insulation ◽  
Large Scale ◽  
Process Development ◽  
System Modeling ◽  
Dielectric Constants ◽  
Thermal Design ◽  
Small Scale ◽  
Thermal Testing ◽  
High Porosity ◽  
Crystal Oscillator

Extreme miniaturization in the microelectronics component market along with the emergence of system-on-chip applications has driven interest in correspondingly small-scale thermal management designs requiring novel material systems. This paper concentrates on aerogel, which is an amorphous, nanoporous dielectric oxide fabricated through a sol-gel process. Its extremely high porosity leads to very low thermal conductivity and dielectric constants. Significant research has been devoted to its electrical properties; however, there are several emerging applications that can leverage the thermal characteristics as well. Two promising applications are investigated in this paper: a monolithically integrated infrared sensor that requires thermal isolation between sensor and silicon substrate, and an ultra-miniature crystal oscillator device which demands thermal insulation of the crystal for low-power operation. This paper identifies the potential benefits of aerogel in these applications through system modeling, demonstrates aerogel’s compatibility with standard low-cost microfabrication techniques, and presents results of thermal testing of aerogel films compared with other microelectronics insulators and available data in the literature. The goal is to explore system thermal design using aerogel while demonstrating its feasibility through experimentation. The combination of numerical simulations, Bayesian surrogate modeling, and process development helps to refine candidate aerogel applications and allow the designer to explore thermal designs which have not previously been possible in large-scale microelectronics system production.   This paper was also originally published as part of the Proceedings of the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems.

Engineering Structure and Properties of Materials Used as a Matrix in Diamond Impregnated Tools / Kształtowanie Struktury I Własnosci Materiałów Stosowanych Jako Osnowa W Narzedziach Metaliczno-Diamentowych

2013 ◽  
Vol 58 (1) ◽  
pp. 5-8 ◽  
Author(s):  
J. Borowiecka-Jamrozek
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Structure And Properties ◽  
Hot Press ◽  
Properties Of Materials ◽  
The Mean ◽  
Materials Used ◽  
Hot Press Process ◽  
Scanning Electron ◽  
And Tungsten

The paper presents mechanical properties of materials used as matrices in diamond impregnated tools. Several powder metallurgy materials were manufactured by the hot press process from various combinations of cobalt (Co SMS, Co Extrafine, Co 400mesh), carbonyl iron (Fe CN) and tungsten (WP30) powders. After consolidation the specimens were tested for density, hardness and tensile properties. The fracture surfaces and materials’ microstructure were observed using the Jeol JSM- 5400 scanning electron microscope and the Leica DM4000 light microscope. The main objective of the work was to determine the effects of the mean particle size of cobalt as well as additions of iron and tungsten on properties of the as-consolidated material.

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