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Thermal analysis of some fly ashes

II. Self-hardening activity of fly ashes

Journal of Thermal Analysis and Calorimetry
Authors: Z. Adonyi and K. Mészáros Szécsényi

The self-hardening activity of fly ashes was investigated looking for the possibility of their chemical reactions with water without additives. A method had to be developed for separation of the structural water from the adsorbed or free one. The decomposition of the chemically bound water was measured by thermogravimetry. The‘I’ dimensionless number proved to be applicable for the quantitative characterisation of the measured data with more DTG peaks. The examined reaction depends on the chemical composition and the physical structure of the fly ashes and the time of interaction with water. The SO3 content seems important, but the characteristics of the formed compounds differ deeply from the CaSO4·2H2O. The observed and examined reaction is an important factor of the self-hardening process of fly ash deposits.

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Abstract  

A method is described for the microdistillation of liquids using quasi-isothermal quasi-isobaric thermogravimetry. The liquidus curve determined under quasi-equilibrium conditions gives useful information about the composition and some thermal properties of the sample. The method could be attractive for the mineral oil, lacquer, biological and organochemical industry.

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Shell eggs have been irradiated with increasing radiation doses in the 0.5-3.0 kGy dose range and various non-microbiological changes, important from the point of view of consumer quality, have been estimated. Dose-dependent changes in the flow behaviour of egg white and brittleness of the yolk membrane in broken eggs, sensorial parameters of the raw and soft-boiled eggs, whippability and foam stability of the egg white were observed. Considering that a minimal dose of 1.5 kGy would be required for radiation inactivation of salmonellae and other, non-pathogenic bacteria, the quality of irradiated eggs upon such gamma radiation dose would not be equal in all parameters to those of the fresh shell eggs, however, changes in sensorial and functional properties at this dose level may be still acceptable, mainly for risk population and some industrial use.

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Acta Physiologica Hungarica
Authors: Zs. Mészáros, K. Kiss, M. Szmodis, M. Zsidegh, M. Mavroudes, and János Mészáros

The aim of the present longitudinal study of four years was to analyse differences in growth patterns, age-related changes in body fat and physical performance in schoolchildren taking part either in normal or in elevated level physical education at school.Nine data collection sessions were carried out between 2002 and 2006 in 18 schools. The sample consisted of 521 non-athletic volunteer boys (PE=116, contrast = 405).The inter-group differences between mean height, body weight, body mass index, relative body fat content, mean scores in 30 m dash, 400 m run, and standing long jump as well as the patterns of change with age were analysed in this comparison. Between-observation differences were tested by repeated measures ANOVA. In case of a significant F-test Tukey’s post-hoc tests were used. Age dependence was also studied by linear regression analysis.The between-group differences in mean height were not significant, but the slope of height increase with age was significantly greater in the PE boys. The PE boys were significantly lighter through all the nine observations and the slope of age-related weight increase was statistically faster in the group of contrast subjects. Both the BMI means and percent body fat means were consistently and significantly greater in the contrast group and faster increases were found in the group of the less active boys. The mean physical performances of the PE boys were consistently and significantly better. Their slopes of increase were statistically different.

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Long-range repeated-measure sample differences in body dimensions, body composition and physical performance help to describe the changes in a population’s lifestyle. The aim of our study was to analyse such changes in longitudinal studies repeated after a 25-year interval. Data collections repeated every six months for the periods 1977–1981 (n=152) and 2002–2006 (n=158) were carried out in nonathletic boys aged between 6.51 and 11.50 years from the same districts of Budapest. Means for height, body mass, BMI, body fat percentage, and distance covered during a running endurance test, as well as the slopes of the changes were compared. The children of the second series of studies were significantly taller and heavier, had more depot fat and showed poorer cardio-respiratory endurance than their peers 25 years before. The increases with age in weight, BMI and depot fat were steeper in the second series. The significant differences that developed in anthropometric traits and physical performance during these 25 years are regarded as indirect evidence for how severely the average physical condition had declined, as well as how health risks of the schoolchildren had increased.

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Acta Physiologica Hungarica
Authors: P. Osváth, Zs Mészáros, Sz Tóth, K. Kiss, M. Mavroudes, N. Ng, and János Mészáros

Fatness generally has a negative influence on the performance of a variety of motor and cardiorespiratory fitness tests. The aim of this comparison was to analyse the effects of three grades of obesity on somatic growth, physical performance and oxygen consumption during exercise. Volunteer boys with definitely different grades of obesity were recruited for the comparison. In the group of mildly obese children (G1; n=23) BMI ranged between 24 kg.m −2 and 26 kg.m −2 ; and individual percent body fat was between 33% and 33.5%. In the case of moderate obesity (G2; n=23) BMI ranged between 26.5 kg.m −2 and 28.5 kg.m −2 ; and percent body fat was between 35% and 36%. In the extremely obese group (G3; n=20) BMI was greater than 31 kg.m −2 ; percent body fat was greater than 37.5%. Oxygen consumption during the 1,200 m run-test was measured by VIMEX-ST-type (USA) telemetric equipment.The greatest absolute aerobic power referred to the G3 boys, and the lowest oxygen consumption was characteristic of the mildly obese group. The very high differences between the body mass means resulted in a more marked inter-group variability in mean relative oxygen uptake.The predicted relative fat and high body fat content observed on the trunk, and the elevated level of resting blood pressure may indicate serious risks for the development of cardio-respiratory and metabolic disease. The very low oxygen consumption relative to body mass and poor physical performance are expected consequences of physiologic and environmental influences on the obese population.

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Acta Physiologica Hungarica
Authors: K. Kiss, Zs Mészáros, M. Mavroudes, M. Szmodis, M. Zsidegh, N. Ng, and János Mészáros

The aim of this comparison was to evaluate the nutritional status and cardio-respiratory fitness of future health professionals, namely university students engaged in medical studies. It was assumed that the lifestyle of such students would be reflected by healthy body composition and fitness performance indicators. Altogether 1,560 volunteer, female, university students of three institutions were investigated in 2008. Height, body weight, BMI, body fat content and 800 m run test means were compared.The height, weight and BMI means did not differ significantly but PE students recorded the lowest mean body fat (18.34% vs. 24.37 and 25.12%) and shortest mean running time (203 s vs. 239 and 243 s). Among the medical (11.23%) and technical university students (19.95%) statistically the same prevalence of obesity was observed.High body fat content and low running performance of medical students were in contrast with our hypothesis. Their prevalence of overweight/obesity and low fitness did not differ from that of relatively sedentary technical university students and the average Hungarian young adult population. Thus, it is questionable how young health professionals will promote the necessity and positive effects of regular physical activity if they do not apply them to their own lifestyle.

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The possibilities latent in molecular marker-based QTL analyses are presented through the example of studying winter survival and heading date in barley (Hordeum vulgare L.). The whole range of QTL experiments consists of several important steps, through which answers are found to the following questions: (1) How many QTLs are involved and where do they map, (2) How does the environment influence the effect of a QTL region (environment × QTL interactions), (3) When and where are the genes determining the given trait expressed (QTL dynamics), (4) What interactions occur between these QTLs and pathways leading to specific phenotypes, and (5) How consistent is the effect of a QTL region in different genetic backgrounds and in a wider range of germplasms (comparative mapping and association studies)? This knowledge then makes it possible to continue these experiments in the direction of marker-assisted selection and/or gene isolation through marker saturation of the relevant chromosomal regions and map-based cloning. The latter can give an insight into the exact mechanism through which the gene determines the phenotype.

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The effect of vernalization response and photoperiod sensitivity on reproductive fitness and agronomic traits was examined in a group of 16 H. spontaneum accessions and 8 H. vulgare cultivars in controlled environments. The whole range of plant developmental and agronomic traits was determined by vernalization. The reproductive fitness was severely impaired when the vernalization requirements of the plants were not saturated. Variation in the magnitude of vernalization response significantly correlated with several traits. A larger decrease in reproductive tiller number, average seed number and consequently final grain yield was more characteristic of accessions with a greater vernalization response. When the vernalization requirement was met, long photoperiod enhanced the fitness of the plants and resulted in larger yield and yield components, irrespective of the genotype, while short photoperiod acted as a limiting factor for all these traits. There was, however, a difference in the reaction type of wild and cultivated genotypes due to their different plant strategies.

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The early growth and tillering capacity of two barley (Hordeum vulgare L.) varieties (Dicktoo and Kompolti Korai) were investigated in a gradient growth chamber. The identification of these crop traits is important under organic agricultural conditions in the selection of new varieties for competitiveness against weeds. The results clearly demonstrate that the initial development of the two barley varieties depended considerably on the plant growth conditions. The temperature gradient was found to have the greater effect during early development, causing significant differences in all the traits at all measurement dates. The results indicate that the two varieties differ substantially for two characteristics important for organic farming. As regards tillering ability, Dicktoo appears to be the more desirable type, despite the fact that it is unable to achieve its tillering potential at higher temperatures. Under certain ecological conditions, the relative temperature insensitivity of Kompolti Korai could be an advantage. As far as early development vigour is concerned, Kompolti Korai is clearly a desirable type for organic farming, since it produced rapidly growing, robust plants in all the temperature ranges. From the point of view of organic breeding, a combination of the valuable traits of these two varieties could be the way forward.

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