Search results for "Mining engineering"
showing 10 items of 60 documents
Surface Morphology of Single and Multi-Layer Silicon Nitride Dielectric Nano-Coatings on Silicon Dioxide and Polycrystalline Silicon
2019
Silicon nitride (Si3N4) in a form of single and multi-layer nanofilms is proposed to be used as a dielectric layer in nanocapacitors for operation in harsh environmental conditions. Characterization of surface morphology, roughness and chemical bonds of the Si3N4 coatings has an important role in production process as the surface morphology affects the contact surface with other components of the produced device. Si3N4 was synthesized by using low pressure chemical vapour deposition method and depositing single and multi-layer (3 – 5 layers) nanofilms on SiO2 and polycrystalline silicon (PolySi). The total thickness of the synthesized nanofilms was 20 – 60 nm. Surface morphology was investi…
The Grain Boundary Wetting Phenomena in the Ti-Containing High-Entropy Alloys: A Review
2021
In this review, the phenomenon of grain boundary (GB) wetting by melt is analyzed for multicomponent alloys without principal components (also called high-entropy alloys or HEAs) containing titanium. GB wetting can be complete or partial. In the former case, the liquid phase forms the continuous layers between solid grains and completely separates them. In the latter case of partial GB wetting, the melt forms the chain of droplets in GBs, with certain non-zero contact angles. The GB wetting phenomenon can be observed in HEAs produced by all solidification-based technologies. GB leads to the appearance of novel GB tie lines Twmin and Twmax in the multicomponent HEA phase diagrams. The so-cal…
A Study of Osmosis Rate Through Several Proton Conducting Polymer Composite Membranes
2021
Carbon dioxide is typically considered to be a byproduct of various industrial processes that should not be released into the environment due to its nature as a harmful greenhouse gas. One of the more promising ways to dispose of it in an economical and environmentally friendly way is by using it as a raw material in electrochemical synthesis reactors. An important part of such reactors is an ion exchange membrane. In this study the influence of ZrO2 content in SPEEK – ZrO2 composite membranes on rate of osmosis trough them was investigated, with the goal of evaluating ZrO2 as an additive for making ion exchange membranes with fine-tuned osmotic permeability.
In situ remediation of polluted Spolic Technosols using Ca(OH)2 and smectitic marlstone
2014
Technosols are soils developed on non-traditional substrates and containing large quantities of materials mostly due to intensive human industrial activity, such as artefacts. The increasing number of sites affected by Technosols and their impact on the environment as growing media for plants or as source of pollutants require an understanding of their functioning and evolution, above all the knowledge on the transport of toxic substances from contaminated technogenic soils to groundwater. A case study on properties, remediation and evaluation of Technosols made up by vitrified fly ash and glass–ceramics in Italy was carried out. Original technogenic soils, classified as Spolic Technosols (…
Green approach to corrosion inhibition of stainless steel in phosphoric acid of Artemesia herba albamedium using plant extract
2019
Essential oil from aerial parts of Artemisia herba-alba from Morocco was hydrodistilled and its chemical composition oil was investigated by capillary GC and GC/MS. The major components were 1,8-cineole (35.6%) and camphor (24.1%). Artemisia herba-alba essential oil AHAO was tested as corrosion inhibitor of stainless steel (SS) in 1M H3PO4 using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy measurements (EIS) and scanning electronically microscopy (SEM) studies. The results obtained showed that the essential oil of Artemisia reduces the corrosion rate. Tafel polarization method indicates that the plant extract behaves as a mixed type inhibitor. The inhibition…
Influence of Biomass Combustion Products on Element Content and Thermal Stability of Latvian Sheep Breed Wool Filter Fibres
2020
Sheep wool is natural, easy obtainable, renewable and biodegradable material with a perspective application as a sorbent in filters for purification of industrial emissions from various environmental pollutants. The element content and thermal stability of Latvian dark-headed sheep wool filter fibres was analysed and described before and after exposure to biomass combustion products. Based on the obtained results, it is concluded that the sheep wool filter fibres can sorb various gaseous combustion products, such as carbon monoxide (CO), carbon dioxide (CO2) and nitrogen oxides (NOx), however, the sorption processes of these gases are irreversible. The obtained results of total reflection X…
The Ignoble Fuel
2012
Perhaps the first historic mention of a substance derived from coal goes back to the Bible, when Yahweh orders Noah to build the famous ark.
Development of Removable Visual Impact Indicator or Polymer Composite Materials
2021
The prototype of removable visual impact indicator for thermoset polymer composite materials is developed, and its characteristics are experimentally determined. The indicator is a fabric tape glued by epoxy to the surface of the polymer composite. The tape is impregnated with a composition that provides a visual response at the place of an impact on the composite surface. Ball-drop tests demonstrated the increase of the magnitude of the visual response with the impact energy at different substrate hardnesses. The shelf-life and mode of the tape storage until commissioning are determined. Peel tests showed the ability to remove a used indicator without damaging the surface of the composite.
Investigations of Latvian Illite/Kaolinite Clays Irradiated Under Action of Accelerated Electrons
2019
Natural clay is a perspective material for application as sorbents for wastewater treatment as well as for sorption of radionuclides, where the properties of the clays can be changed under influence of ionizing radiation. For application of Latvian illite/kaolinite clays for isotope sorption it is important to characterize the physic-chemical properties of pre-prepared air dried clays. Two fractions of the illite clays were selected. A fraction with grain size 100 μm (SiO2 content 60.9 ± 1.5 wt.%, specific surface area 35 m2/g) and a sand free fraction – 2 μm (SiO2 47.7 ± 1.9 wt.%, specific surface area 38 m2/g). Selected fractions were irradiated with accelerated electrons (5 MeV, ELU-4, S…
E-maintenance platform: a business process modelling approach
2014
Las tecnologías de la información y la comunicación (TIC) se utilizan cada vez más en la sociedad y en los negocios. Las TIC se han convertido en un elemento clave para el desarrollo empresarial y la mejora de las actividades en todos los departamentos de una organización. Análogamente, la creciente importancia de los Sistemas de Gestión de Mantenimiento asistido por Ordenador (CMMS), Mantenimiento Basado en la Condición (CBM), y la aplicación de dispositivos remotos y funciones como el e-mantenimiento, han abierto grandes posibilidades para la optimización del mantenimiento. Estas técnicas han dado lugar a la aparición de retos tecnológicos, tales como la interoperabilidad entre diferentes…