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Dizaina, vides un ražošanas tehnoloģiju laboratorija / Design, Environment, and Production Technology Lab
87 results
Now showing 1 - 10 of 87
- PublicationLake blue clay - sapropel - flax shive briquettes for water absorption and desorption(2018)
; ; - PublicationEvaluation of laser cutting process with auxiliary gas pressure by soft computing approach(2018)
; ; Nebojsa ArsicEvaluation of the optimal laser cutting parameters is very important for the high cut quality. This is highly nonlinear process with different parameters which is the main challenge in the optimization process. Data mining methodology is one of most versatile method which can be used laser cutting process optimization. Support vector regression (SVR) procedure is implemented since it is a versatile and robust technique for very nonlinear data regression. The goal in this study was to determine the optimal laser cutting parameters to ensure robust condition for minimization of average surface roughness. Three cutting parameters, the cutting speed, the laser power, and the assist gas pressure, were used in the investigation. As a laser type TruLaser 1030 technological system was used. Nitrogen as an assisted gas was used in the laser cutting process. As the data mining method, support vector regression procedure was used. Data mining prediction accuracy was very high according the coefficient (R2) of determination and root mean square error (RMSE): R2 = 0.9975 and RMSE = 0.0337. Therefore the data mining approach could be used effectively for determination of the optimal conditions of the laser cutting process. - PublicationLASER ABLATION OF PAINT COATINGS IN INDUSTRY(2021)
; ; ; ; A comparison is made between the laser and sandblasting methods for removing paint from industrial facilities. The advantages of laser ablation are discussed. The possibilities of laser paint removal systems - stationary and moving - are shown. The main factors influencing the laser ablation process and the indicators that determine the quality of the obtained surface are systematized. Researchers' publications on this technological process are analyzed. - PublicationMARKET ANALYSIS OF EXTRUDED FIELD BEAN FLOUR FOOD PRODUCT POTENTIAL(2021)
; The consumption of functional food is increasing in almost all industrialized countries, not only because of an aging population but also because of a more enthusiastic lifestyle, which makes meeting the nutritional requirements more difficult. In part, the transition to processed, easily packaged and pre-cooked foods is considered to be a response to long working hours. It resulted in an increased demand for ready-to-eat foods in recent years and it is expected to continue growing. The aim of the research is to study and analyse the need for extruded field bean flour food products in the market. Methods used in the research – monographic, synthesis, statistical analysis methods. The research developed proposals for the sale of extruded field bean flour as a food raw material in different markets. - PublicationEffect of Polysorbates on the Growth of Rhodotorula Glutinis in Oil Rich Medium(2021)
; Dagnija BlumbergaThe present study has investigated the effect of oil rich medium supplementation with polysorbates Tween 20, 40 and 80, for the cultivation of red oleaginous yeast Rhodotorula glutinis. R. glutinis has been cultivated in yeast extract peptone glucose modified broth (mYPG) supplemented with 2 % of waste cooking rapeseed oil and three polysorbate types with 0.5 %, 1 %, 2%, 3 %, 4 %, 5 %, 6 %, 7 %, 8 %, 9 % and 10 % concentration each. Yeast biomass was measured by the thermogravimetric method at 105 °C each day during 7-day experiment. The oil rich medium supplementation with Tween 20, 40 and 80 at concentrations ranging from 2 % to 10 % significantly increased the biomass of R. glutinis. All three types of the studied polysorbates with 0.5 % and 1 % concentration, did not affect yeast growth and the dry biomass – results were similar to the control sample without polysorbate addition. Between the three types of polysorbates, Tween 20 was selected as the preferable for R. glutinis cultivation with an optimal concentration of 2 %. Cultivation of R. glutinis in oil rich medium with polysorbates Tween 20, 40 and 80, supplementation up to 10 % concentration did not have had an inhibitory effect on the biomass growth. - PublicationDistribution of iron and iron compounds in the Kemeri - Jaunkemeri occurence of sulphide water(2015)
; Iron concentrations, distribution and migration forms, depending on pH and oxidation – reduction potential, were analyzed in case of the Kemeri-Jaunkemeri occurrence (area about 240 km2) of sulphide containing water (maximal sulphides concentration – 74 mg/l), located in Latvia. Iron content was investigated in 457 wells located within all area of occurrence. Those wells were installed to two aquifers: the Quarternary multi-aquifer and Salaspils aquifer, where occurrence of sulphide containing groundwater is distributed. All groundwater of occurrence is classified in four types depending on oxygen, sulphides and organic matter content in the groundwater. Modeling of groundwater migration forms was carried out, and it is stated that iron migrates basically as Fe2 in oxygen and suphides non-containing water. Migration forms are influenced by concentration of organic matter in the aquifer. The portion of Fe2 migrating in a form of free decreases due to formation of complexes with fulvic and humic acids, which can reach 36.5% of all migration forms. Iron migrates as Fe(OH)3 in oxygen containing water (more than 99% of determined forms). Presence of iron is ascertained also in sulphides containing water, where iron migrates basically as (98.8% of determined forms). This occurs due to formation of complexes with sulphydes – FeHS- and Fe(HS)2o. - PublicationLASER AS A DEVICE FOR MEASUREMENT OF THIN THREADS - A SCHOOL LABORATORY EXPERIMENT IN PHYSICS(2017)
; The physics of the last century is included in all EU curricula and emphasis in education is shifted from content to the forms, methods and means of teaching and learning. Different kinds of lessons (including laboratory classes) and their didactic structure are subject to the understanding, adoption and creating conditions to build motivation to learn physics and astronomy, active utilization of physical knowledge and building cognitive and practical skills. Performance of demonstration and laboratory classes using a laser device is a type of teaching strategy to good education in physics. Properties of laser light as observation, classification, communication, drawing conclusions, planning, interpretation and forecasting, are particularly suitable when monitoring and studying the phenomena of interference and diffraction. Through both qualitative and quantitate ways, in this paper is presented a physical experiment for measurement of thin threads in a High school from students. Experimental skills will enhance interest in physics and especially to modern applications of laser devices, as well as career guidance of students. - PublicationTHE APPLICATION OF HEMP IN BIOECONOMY(2021)
; - PublicationPlate Waste Forecasting Using the Monte Carlo Method for Effective Decision Making in Latvian Schools(2022)
; ; Scopus© Citations 2 - PublicationEvaluation of Students’ Research Activities in the Design Study Programmes at Rezekne Higher Education Institution(2015)Nowadays education and research is promoting development of design industry. In order to find unique Latvian design identity the quality of design is increasing. New possibilities and requirements for design education and research are raised by social and ecological issues. In order to promote sustainable design education research strategy is needed, therefore it is essential to pay attention to research strategy in education process. The aim of the article is educational research as significant part of research competence theoretical and empirical evaluation and its activation in design courses' education process in Rezekne Higher Education Institution. The analysis of the learning research process was carried out in accordance with the principles of action research, theoretical researches in the context of the issue were carried out and the results were obtained: opinions of 80 full time students in the age group 19-25 years, about the role of learning research process of designers' education. The research has practical meaning, because it recommends suggestions for perfection of study process in connection to investigation and analysis of educational research promoting/delaying activities, and necessity to promote students' research competence for professional project work in the future.