Examining erosion resistance of ceramics for electrical engineering applications

In this research, two non-destructive testing (NDT) methods, thermal vision analysis and image analysis, were implemented for monitoring the surface changes- erosion of mullite based ceramic samples in conditions of cavitation exposure. Thermal imaging analysis was focused on determining temperature line profile at the end of the cavitation experiment. Image analysis is a powerful tool for quantification of degradation level caused by different impacts and conditions. Based on the results of image analysis, the degradation level during the testing was determined, as well as number of formed pits with their characteristics (average diameter and area). The results performed by both methods were discussed in order to obtain optimal procedure that should be followed for estimating degradation caused by cavitation erosion

Possibilities of Using Sulfur for Concrete Production and its Application

Two types of concrete will be shown in this paper. First type of concrete is sulfur concrete, where part of Portland cement was replaced with sulfur. Second type of concrete is selfcompacting concrete, where sulfur replaced part of the filler, with different contents. Analysis of the required amount of sulfur for these types of concretes, as well as the influence on the quality achieved and potential application in objects for Renewable energy, will be discussed

Fizička i nedestruktivna ispitivanja keramičkih materijala za oblaganje sa aspekta trajnosti

U radu su prikazane osnovne metode ispitivanja materijala, koje mogu poslužiti prilikom prve faze procene kvaliteta materijala, nakon degradacije usled vremena ili drugih faktora koji mogu izmeniti fizičko-mehanička svojstva materijala. Nedestruktivna metoda ispitivanja pomoću praćenja brzine prostiranja ultrazvučnog impulsa upotrebljena je radi ilustracije mogućeg pristupa pri proceni kvaliteta različitih tipova keramičkih materijala za oblaganje

The Basic Aspects of Wind Turbine Foundations in Our Conditions

Following the global trends and accordingly to the energy conditions, wind turbines are being succesfully built in Serbia, which leads to an increase in the fund of knowledge in this field. In the paper, on the basis of general geotechnical conditions in Serbia, the most common types of wind turbine foundations will be presented. Problems of the load analysis of these structures will be presented in brief, and also the conceptual requirements in their design. Connection between the tower and the foundation will be briefly described as well. Despite the global aspiration to eneralize and industrialize this aspect of the construction of wind turbines, in specific cases remains a number of issues, regarding component materials, the application of standards and design codes, which are usually not adjusted to the design of wind turbine foundations

Relevant Properties of Green Self-Compacting Concrete

The production of durable concrete with a high content of supplementing cementitious materials and recycled aggregate presents a step towards sustainability in the concrete industry. The paper presents the findings of the study, conducted on four series of concrete with self-compacting properties, which embodied recycled concrete aggregate, as a substitution for natural sand and gravel. Besides, this concrete possessed high content of fly ash, therefore qualifying as ecological (green) one. Particle packing method was used in the design of this concrete. Fresh properties included: density, slump flow, V-funnel, L-box and temperature, while compressive and tensile strengths were evaluated in the hardened state. Although certain difficulties in the application were recognized concerning the fast loss of workability in the fresh state, all of the tested mixtures exceeded the requirements of hardened structural concrete

High temperature materials: properties, demands and applications

High-temperature materials are used in a wide range of industries and applications such as gas turbine engines for aircrafts, power and nuclear power plants, different types of furnaces, including blast furnaces, some fuel cells, industrial gas turbines, different types of reactors, engines, electronic and lighting devices, and many others. Demands for high-temperature materials are becoming more and more challenging every year. To perform efficiently, effectively and at the same time to be economically viable, the materials used at high temperatures must have certain characteristics that are particularly expected for applying under such extreme conditions, for example, the strength and thermal resistance. In the present review, some important requirements that should be satisfied by high temperature materials will be discussed. Furthermore, the focus is put on refractory concretes, ceramics, intermetallic alloys, and composites as four different categories of these materials, which are also considered in respect to possibilities to overcome some of the current challenges

Basic principles of 3D concrete printing in the light of sustainable development

Although conservative, the construction industry must be transformed in line with new technologies. Adopting the concept of 3D printing can provide a handful of benefits in terms of creativity, flexibility, less waste generation, more efficient energy consumption as well as lower carbon emissions. The aim of this paper is to summarize the basic principles of 3d concrete printing, discussing the main goals and shortcomings that must be considered and resolved before wider application. Also, a review will be given on the production technology and materials used, as well as the sustainability of buildings built using the concept of 3d printing

Copper removal by pelletized fly ash

The increasing levels of industrial wastewater that are released to the environment present a serious threat to human health, living resources, and ecological systems. Fly ash was tested for the removal of Cu2+ from contaminated water in a micronized and pelletized form. Experiments were performed for a wide range of initial concentrations of Cu 25-600 mg dm-3. Pellets fraction size was 2.0-3.5 mm, while the content of cement, as a binder was 10%. Under applied experimental conditions pellets manifested exceptional adsorption capacity (25.64 mg/g) that was three times higher compared to the micronized fly ash (8.85 mg/g)

Monitoring efekata toplote hidratacije betona

U ovom radu su praćeni efekti toplote hidratacije različitih betona upotrebom termovizijske kamere i termodavača priključenih na osmokanalni sistem za monitoring temperature na bazi PC i LabVIEW paketa, razvijen za potrebe ovog istraživanja. Temperatura ambijenta (laboratorije) beležena je i memorisana pomoću posebnog digitalnog instrumenta. Praćenje temperature svežeg betona je trajalo 24h. Vršena su poređenja temperatura površine izmerenih termodavačima i termovizijskom kamerom. Na osnovu toga uspostavljene su korelaciju koje bi mogle dovesti do pojednostavljenja daljih ispitivanja, posebno masovnih