Thermomechanics of soft inelastics bodies with application to asphalt behavior

Thermomechanical behavior of hot mix asphalt (HMA) is considered. Its highly irregular microstructure is covered by the hierarchical approach. A brief survey of endochronic thermodynamics precedes constitutive consideration. Two constitutive models are discussed: classical Perzyna's approach and tensor representation based approach. The second is superior due to its possibility to cover properly diverse multiaxial non-proportional stress-strain histories. However, due to availability of experimental data the first model is applied to rutting problem through Abaqus FEM code with material user subroutine developed by the authors. Vakulenko's thermodynamic time appropriate for aging is incorporated. Hyper elastic-viscoplastic behavior is considered and some preliminary results are presented

Thermomechanics of soft inelastics bodies with application to asphalt behavior

Thermomechanical behavior of hot mix asphalt (HMA) is considered. Its highly irregular microstructure is covered by the hierarchical approach. A brief survey of endochronic thermodynamics precedes constitutive consideration. Two constitutive models are discussed: classical Perzyna's approach and tensor representation based approach. The second is superior due to its possibility to cover properly diverse multiaxial non-proportional stress-strain histories. However, due to availability of experimental data the first model is applied to rutting problem through Abaqus FEM code with material user subroutine developed by the authors. Vakulenko's thermodynamic time appropriate for aging is incorporated. Hyper elastic-viscoplastic behavior is considered and some preliminary results are presented

Employing machine learning to assess the accuracy of near-infrared spectroscopy of spent dialysate fluid in monitoring the blood concentrations of uremic toxins

Hemodialysis (HD) removes nitrogenous waste products from patients’ blood through a semipermeable mem- brane along a concentration gradient. Near-infrared spectroscopy (NIRS) is an underexplored method of monitoring the concentrations of several molecules that reflect the efficacy of the HD process in dialysate samples. In this study, we aimed to evaluate NIRS as a technique for the non-invasive detection of uremic solutes by assessing the correlations between the spectrum of the spent dialysate and the serum levels of urea, creatinine, and uric acid. Blood and dialysate samples were taken from 35 patients on maintenance HD. The absorption spectrum of each dialysate sample was measured three times in the wavelength range of 700-1700 nm, resulting in a dataset with 315 spectra. The artificial neural network (ANN) learn- ing technique was used to assess the correlations between the recorded NIR-absorbance spectra of the spent dialysate and serum levels of selected uremic toxins. Very good correlations between the NIR-absorbance spectra of the spent dialysate fluid with serum urea (R=0.91) and uric acid (R=0.91) and an excellent correlation with serum creatinine (R=0.97) were obtained. These results support the application of NIRS as a non-invasive, safe, accurate, and repetitive technique for online monitoring of uremic toxins to assist clinicians in assessing HD efficiency and individualization of HD treatments

Radioactivity of fungi in schist-type soil in the Stara Planina mountain ecosystem

Mountain ecosystems are going through changes due to numerous physical-chemical processes in the environment rather than the anthropogenic activities. Primordial radioactivity of rock and soil material migrates and fractionates in other environmental sections like waters, air and biota. Having a feature to accumulate different minerals and trace element present in soil and three substrates, fungi indicates their composition and related processes. The aim of this study is uptake of radionuclides by fungi in the schist soil of the Stara Planina, mountain famous for biodiversity as well as for enhanced natural radioactivity areas. Samples of various fungi species (stipes and cups) and their soil substrates have been collected in summer season 2019. Collected soil samples are pedologically characterized and analysed by gamma-spectrometry (HP Ge) after the secular radioactive equilibrium had been reached. Soil characterization has shown the share of coarse fragments, sand, silt and clay in the schist (shale) structure while pH value was 4.80-5.33 and organic carbon content 3.10%. The content of significant natural radionuclides 40K, 226Ra, 232Th, 238U and manmade 137Cs was (in Bq/kg) was 500±30, 27±2, 26±2, 32±4, 1.6±0.2 respectively. Dried fungi samples were analysed by gamma spectrometry showing the natural radionuclide content in wide range of values. Obtained results indicate dependence of the radionuclides uptake from the substrate on their abundance in schist soil type as well as the fungus specie physiology. Slight difference was observed in results between content in species with different types of nutrient uptake (mycorrhizal and saprobic). The 137Cs content varied from 2-20 Bq/kg. Further knowledge on the local population habits in use of edible fungi species would enable dose assessment for the representatives of the public and contribute to a further research on the Stara Planina mountain ecosystem.X JUBILEE International Conference on Radiation in Various Fields of Research : RAD 2022 (Summer Edition) : book of abstracts; July 25-29, 2022; Herceg Novi, Montenegr

The crystal growth of NASICON phase from the lithium germanium phosphate glass

The crystal growth rate of LiGe2(PO4)3 phase from lithium germanium-phosphate glass was studied. The glass have been homogenized using the previously established temperature-time conditions, which make it possible to remove volatile substances from the glass melt. The atomic absorption spectrophotometry (AAS) was used to determine the chemical content of the obtained glass and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth. The crystal growth rates were determined experimentally and theoretically

The analysis of the crystal growth process of the lithium germanium phosphate glass : [invited presentation]

The crystal growth rate of lithium germanium-phosphate glass was studied. The glasses have been homogenized using the previously established temperature-time conditions, which make it possible to remove a volatile substances from the glass melt. The AAS was used to determine the chemical content of obtained glass, the differential thermal analysis (DTA), and scanning electron microscope (SEM) were used to reveal the isothermal process of crystal growth, respectively. It has been found that the experimental determined crystal growth rate has a tendency toward of exponentially increase with an increase the temperature

The impact of educational reform and categorization of scientific journals and scientists on physics in Serbia

The trend of the increasing participation and importance of female physicists in Serbia continues. Many women have taken leading position in research and faculty governance and are contributing significantly to educational reform and the improvement of physics education in the primary and secondary schools

Age- and season-dependent pattern of flavonol glycosides in Cabernet Sauvignon grapevine leaves

Flavonols play key roles in many plant defense mechanisms, consequently they are frequently investigated as stress sensitive factors in relation to several oxidative processes. It is well known that grapevine (Vitis vinifera L.) can synthesize various flavonol glycosides in the leaves, however, very little information is available regarding their distribution along the cane at different leaf levels. In this work, taking into consideration of leaf position, the main flavonol glycosides of a red grapevine cultivar (Cabernet Sauvignon) were profiled and quantified by HPLC–DAD analysis. It was found that amount of four flavonol glycosides, namely, quercetin-3-O-galactoside, quercetin-3-O-glucoside, kaempferol-3-O-glucoside and kaempferol-3-O-glucuronide decreased towards the shoot tip. Since leaf age also decreases towards the shoot tip, the obtained results suggest that these compounds continuously formed by leaf aging, resulting in their accumulation in the older leaves. In contrast, quercetin-3-O-glucuronide (predominant form) and quercetin-3-O-rutinoside were not accumulated significantly by aging. We also pointed out that grapevine boosted the flavonol biosynthesis in September, and flavonol profile differed significantly in the two seasons. Our results contribute to the better understanding of the role of flavonols in the antioxidant defense system of grapevine

Inquiry about key dimensions of service qualities and guests satisfaction in restaurants

A lot of marketing experts in catering, restaurants especially, have recently been preoccupied by measuring the service quality. Business in competitive and turbulent surrounding requires that restaurants continually improve their products, which is based on guests specific demands and wishes. Comprehension of how consumers see catering offer and research on factors that determine consumers satisfaction are the key for achieving business aims. The aim of this study is an identification of key components of service qualities which restaurants and their influence on guests satisfaction offer. Measures of descriptive statistics, explorative factor and multiple regressive analysis were used in order to achieve the aims of the research. The facts were collected by using the survey. Results of the research highlight 3 key elements of the service quality that restaurants offer and those are: professionalism of personnel, understanding of guests, paying individual attention and meeting specific demands. The first two components include attributes that evince statistically important influence on guests satisfaction. Finds of conducted survey help managers and restaurateurs determine factors they will focus on during the making marketing strategy which will supply high level of consumers satisfaction on one side, and long-term profitability on the other side

Syllable-based speech recognition using electromyography and decision set classifier

© 2015 National Taiwan University. During the speech, contractions of muscles in the speech apparatus produce myoelectric signals that can be picked up by electrodes, filtered and analyzed. The problem of extraction of speech information from these signals is significant for patients with damaged speech apparatus, such as laryngectomy patients, who could use speech recognition based on myoelectric signal classification to communicate by means of the synthetic speech. In the most previously conducted research, classification is performed on a ten word vocabulary which resulted in a good classification rate. In this paper, a possibility for myoelectric syllable based speech classification is analyzed on a significantly larger vocabulary with novel decision set based classifier which is simple, easy to adapt, convenient for research and similar to the way humans think. In order to have a high quality of recorded myoelectric signals, analysis of the optimal position of electrodes is performed. Classification is performed by comparison between syllable combination and whole words. Based on classification rate, words can belong to easy, medium or hard to distinguish group. Results based on generated list of best matching combinations show that decision set analysis of myoelectric signals for speech recognition is a promising novel method