18420 research outputs found
Sort by
Mechanical Properties of Cement Paste with Glass Cullet
No full textAn experimental study was carried out to investigate the effects on the mechanical properties of concrete with finely ground waste glass as Portland cement partial substitution at levels of 30%. Glass cullet (clear, amber, emerald green bottle glass), borosilicate DRL and lead LB fluorescent lamp glass chippings were ground within 60 minutes in laboratory planetary ball mill Retsch PM400 (with rotation speed 300 min-1) into powder. Portland substitution with ground DRL fluorescent waste glass suspension and amber glass cullet powder at level of 30% has shown the best results at the age of 7days, what is very important for structural elements, with 82 and 75Mpa accordingly compressive strength values in comparison to reference mix
Investigation of Thermal Properties of Cement Paste with Fluorescent Lamp Waste Glass and Coal/Wood Ashes
No full textThe thermal character of cement hydration reactions causes concrete to endure temperature changes during the first days after casting. The present research intends to evaluate the influence on the temperature of hydration of cement paste mixes with local industrial wastes such as fluorescent lamp waste glass powder/suspension, glass cullet, bottom/fly coal/wood ashes substitution at level of 20% and 30%. The temperature of hydration of cement paste mixes was investigated by using specially designed equipment. The temperature of hydration inside of the cement paste specimens was continuously monitored at least up to 20 h after production at ambient air temperature 20±2°C. The results showed that cement paste substitution with fluorescent lamp waste glass and coal/wood bottom ashes at level of 30% has influence on the peak temperatures of hydration with decrease from 58.8°C to 46.3°C and cement paste substitution with flint glass at level of 20% decrease temperature of hydration for around 19°C in comparison to control cement paste mix.
Vadības grāmatvedība: teorija un prakse
No full textApskatīts, kā paaugstināt uzņēmējdarbības efektivitāti, izmantojot vadības grāmatvedības specifiskās metode
Ultra Violet Radiation Regulates Wettability Property on PMMA
No full textThe contact angle depends on UV exposure. The UV radiation could be employed to functionalize PMMA wettability, the structure uninfluenced radiation mode being available at exposure < 60 min
Towards Knowledge Management System for Quality Management: Improving Effectivity of Organisations
No full textBoth knowledge management and quality management enable organizsations to operate successfully in dynamic and turbulent environment. A knowledge management system for quality management therefore is seen as a means of enhancing effectivity of organisations
Development of Craft in Latvia and Craftsmen Assessment System
No full textStrengthening of domestic production is a basis for the evolution of Latvian national economy. Craft is an industry which utilizes local materials thus it facilitates the development of national individuality. State measures in legal, organizational and economic sphere are studied in this article. The aim of the measures is to progress craft industry after restoration of independence in Latvia. It is investigated the problems of the development of craft enterprises. One of the problems is effective utilization of labor force and lack of assessment system. This study suggests a system for labor resource evaluation in the craft business, which includes qualitative criteria group and its evaluation, quantitative criteria group and its evaluation and the summary of results in the form of matrix with four quadrants
Increase of Higher Education Efficiency as a Major Factor of Business Development
No full textDuring the period of transition to the Economy based on knowledge, education plays the most important role and, first of all, the Higher education. The following article deals with the level of Higher education in Latvia and its problems are defined. Due to the increase in the investments in the Higher education, the estimation of the efficiency in the Higher education becomes essential . The authors of the article suggested the quantitative method of estimation of the efficiency of investment in the Higher education; investments in different higher schools in Latvia are compared. The comparative analysis
of investments among the study programs of Riga Technical university. This method maybe used for comparison of the effectiveness of investments both in higher schools generally and in separate programs
Inovācijas vadības grāmatvedībā
No full textTezēs tiek aplūkoti faktori, kuri ietekmē vadības grāmatvedības sistēmas attīstību, un jaunas inovatīvas pieejas vadības lēmumu pieņemšanā
Efficient Bandwidth of 50 GHz Fiber Bragg Grating for New-Generation Optical Access
No full textAuthors have measured differential group delay of fiber Bragg grating band-pass filter with 50 GHz full width half maximum bandwidth with method based on Jones Matrix Eigen-analysis and have evaluated efficient bandwidth employing 2.5 Gbit/s and 10.3125 Gbit/s optical signals to draw out limitations for realization of dense wavelength division multiplexing-direct broadband access system