Probabilistic concept and its application in geotechnical stability analyses

Subject of scientific research conducted within this thesis are geotechnical stability analyses, in which the definition of an appropriate soil model due to the complexity of the material (soil) and uncertainties inherent in the influencing factors (soil parameters and load) is difficult. Research methods are dictated by the nature of the problem which is the subject of research. Modeling of soil for geotechnical stability analysis is based on the identification of input parameters (soil characteristics and load), entering their numerical values (constant - for deterministic analysis, and probability distribution functions to describe the range of possible values of each parameter - for purposes of applying the probabilistic concept of stability analysis). Comparative stability analysis of each of a series of selected typical geotechnical problems is performed using the first deterministic, then probabilistic concept. The limitations of traditional deterministic approach are that it does not consider the uncertainty of input parameters and does not provide information on the probability of failure. The task of research is to provide a detailed insight into the structure of stability analysis procedures based on a probabilistic concept, where each input parameter is defined by the range of possible values and a probability distribution function. The results clearly show the advantages of probabilistic approaches in stability analysis and the need for its wider application in our community

The impact of strength training on the changes in one’s physique and resting energy expenditure

Background and Purpose: The aim of this research is to determine the way in which the strength training affects the changes in one’s physique and resting energy expenditure. Materials and Methods: 16 sedentary subjects completed strength training for seven weeks, 3 training/week. The examinee’s physique has been analyzed through bioelectrical impedance method (BIA) before and after the seven-week cycle. The variables compared are BW (body weight), WHR (waist-hip ratio), PBF (percent of body fat) and BMR (basal metabolic rate). The differences between the initial and final values have been tested by paired t-test. The correlations between those differences have been expressed by the Pearson correlation coefficient. The level of statistical significance is p=0, 05. Results: The results indicate that the strength training, even in relatively restricted time period, influences the changes in person’s physique, as well as the changes in resting energy expenditure. The mean difference for BMR (p=0.0036), WHR (p=0,022), PBF(p=0,0184) and BW (p=0.0275) have been established for the entire sample. For the males differences were found for BMR (p=0,002), PBF (p=0,0417) and BW (p=0.0280), but no significant change in WHR. No statistically significant changes were found in female group. Correlation was found for differences in results for BMR vs BW r=0.698 (p=0.003), BMR vs WHR r=-0.578 (p=0.019), and PBF vs WHR r=0,671 (p=0,004). Conclusions: The overall changes in one’s physique and energy expenditure indicate that the strength training needs to be one of the crucial factors in physical activity, aimed at the improvement of person’s health

Possibilities of use bioelectrical impedance analysis as measuring technique in prevention of osteoporosis

Background and Purpose: Bioelectrical impendance analysis (BIA) and dual energy X-ray absorptiometry (DXA) are the two most common methods used for body composition analysis. The aim of this study was to investigate if there is a correlation between results of body analysis by BIA and results of DXA measurements at usual sites for diagnosis of osteoporosis. If the correlation is found than it could mean that BIA might be used to point the need for extra DXA measurements, and earlier diagnosis of osteoporosis. Material and Methods: 27 young adults (11 males and 16 females) aged 19-23 years were measured by BIA instrument for body composition analysis, and by DXA instrument for BMD and BMC at the L1-L4 vertebrae of the lumbar spine postanteriorly and the proximal femur („hip”). Correlation coefficients were calculated to examine linear relationship of results of two methods. Results: Mineral content obtained by BIA correlates with BMC (result of DXA) at all three measured sites. When analyzed by sex, correlation was found only among female subjects, while in males there was no correlation. Correlation of other results of BIA and BMD or BMC (DXA) showed similar situation. T-scores correlated positively with results of BIA within the female subgroup of the sample. Conclusions: According to obtained results we cannot conclude that results of BIA body composition analysis could be indicative for problems in bone metabolism, or state of bone density and bone mineral content, although some correlations are present

Statistička obrada rezultata međulaboratorijskog ispitivanja granulometrijskog sastava peska i šljunka iz zapadnog dela kostolačkog basena

This paper presents the results of interlaboratory testing the grain-size distribution of sand and gravel on representative samples from the site of the western part of the Kostolac Basin. The results were statistically processed by two ways: Numerical method: the Cochran test of accuracy and Graphic interpretation: the MANDEL technique of consistency in accordance with the Standard SRPS ISO 5725-2 [1,2]. The followings were calculated: repeatability variance Sr2; interlaboratory variance SL 2 and reproducibility variance SR 2. Samples were submitted by sharing method to all participating laboratories.U radu su prikazani rezultati međulaboratorijskog ispitivanja granulometrijskog sastava peska i šljunka, na reprezentativnim uzorcima, sa lokaliteta zapadnog dela kostolačkog basena. Rezultati su statistički obrađeni na dva načina i to: Numeričkom metodom: Cochran-ov test preciznosti i Grafičkom interpretacijom: MANDEL-ova tehnika konzistentnosti u skladu sa standardom SRPS ISO 5725-2 [1,2]. Izračunate su: Varijansa ponovljivosti Sr2; međulaboratorijska varijansa SL 2 i varijansa obnovljivosti SR 2. Uzorci su metodom deljenja dostavljeni svim laboratorijama učesnicama

Weight Status and Body Composition in Freshman Students at the College of Applied Sciences “Lavoslav Ruzicka” in Vukovar, from 2008 to 2016

Aim: The aim of the study is to analyze the common occurrence of different weight categories among first-year students at Lavoslav Ruzicka College for Applied Sciences in the city of Vukovar, as well as to make an assessment of their body composition. Methods: During the period from 2008 to 2016 there were 710 first-year students (461 women and 249 men) whose height and weight were measured, and body composition assessed, by bio-electric impedance analysis. Results: Most of the subjects were of normal weight (74.5%), while the ratio between the weight status categories of men has proven to be significantly different from that of women. It was established that 8.9% of women as opposed to 2% of men were below normal weight, while there were more obese individuals among men (25.7%) than there were among women (15.4%). However, the percentage of obesity was similar in both sexes, being 5.4% in women and 5.2% in men. There was no significant difference in the ratio between the weight categories during the measurement period. Conclusion: Most of the students at the College for Applied Sciences fall in the normal weight category. There are more obese individuals among men, while among women there are more of those with lower average body weight. The dominance of obesity and the overall ratio between the weight categories and the body composition in the category of first-year students have not changed significantly during the period between 2008 and 2016

COMPARATIVE ANALYSIS OF ATTERBERG’S LIMITS OF FINE-GRAINED SOIL DETERMINED BY VARIOUS METHODS

Determination of the Atterberg’s limits is necessary for the classification of fine-grained soil. That limits can be determined according to the valid standard SRPS EN ISO 17892-12. Two methods are prescribed by the standard for determining the liquid limit: the Casagrande cup and the Fall Cone test, and one method for determining the plasticity limit: the thread-rolling method. In this paper the Fall Cone method was also used as an alternative method to determine the plastic limit. Ten samples of various fine-grained materials, originating from the wider area of the city of Niš, were tested. The classification of all samples was performed based on the results obtained by the methods prescribed by the standard and alternative methods. Comparative analysis shows that the results obtained by applying standard and alternative methods are close, but also that the scattering of results obtained by the Fall Cone method is significantly less, whereas the reproducibility is higher

Changes in Blood Pressure After Single Bout of Aerobic Exercise in Young Healthy People- Influence of Body Composition

Amount of change in blood pressure after exercise is related to risk of hypertension and cardiovascular diseases. The aim of this study was to determine whether there is a difference in the amount of change of blood pressure after exercise among people with different morphological characteristics, especially with differences in percent of body fat. 30 healthy subjects (15 males and 15 females) aged 25-30 years were included in the study. They were measured for weight and height, and their body composition was assesed by bioelectrical impendance device GAYA 357. Blood pressure was measured at rest and immediately after performing Cooper´s test. After classification of subjects according to BMI (body mass index) and according to percent of body fat (PBF) differences in the size of change in blood pressure among categories were compared. Results indicate that there is no difference between sexes in amount of change for DBP, but there is difference in change of SBP; in males this change was significantly higher than in females. We also found difference in SBP results at rest between different categories of BMI (p=0,023), that was not influenced by gender, while the difference between categories based on different PBF were under the influence of gender. Based on results conclusion can be made that percent of body fat is a factor that influence amount of change in blood pressure with exercise, and is potentially important, and could be predictive factor, like BMI or together with it, in determining the risk of hypertension in young healthy people

Health-related quality of life in elderly patients hospitalized with chronic heart failure

Background: Chronic heart failure is a very common condition in the elderly, characterized not only by high mortality rates, but also by a strong impact on health-related quality of life (HRQOL). Previous studies of HRQOL in elderly heart failure subjects have included mostly outpatients, and little is known about determinants of HRQOL in hospitalized elderly population, especially in Serbia. In this study, we tried to identify factors that influence HRQOL in elderly patients hospitalized with chronic heart failure in Serbia. Methods: The study population consisted of 136 patients aged 65 years or older hospitalized for chronic heart failure. HRQOL was assessed using the Minnesota Living with Heart Failure questionnaire. Predictors of HRQOL were identified by multiple linear regression analysis. Results: Univariate analysis showed that patients with lower income, a longer history of chronic heart failure, and longer length of hospital stay, as well as those receiving aldosterone antagonists and digoxin, taking multiple medications, in a higher NYHA class, and showing signs of depression and cognitive impairment had significantly worse HRQOL. Presence of depressive symptoms (P lt 0.001), higher NYHA class (P=0.021), lower income (P=0.029), and longer duration of heart failure (P=0.049) were independent predictors of poor HRQOL. Conclusion: Depressive symptoms, higher NYHA class, lower income, and longer duration of chronic heart failure are independent predictors of poor HRQOL in elderly patients hospitalized with chronic heart failure in Serbia. Further, there is an association between multiple medication usage and poor HRQOL, as well as a negative impact of cognitive impairment on HRQOL. Hence, measures should be implemented to identify such patients, especially those with depressive symptoms, and appropriate interventions undertaken in order to improve their HRQOL

APPLICATION OF MINDLIN'S THEORY FOR ANALYSIS OF FOOTING PLATE BENDING BASED ON EXPERIMENTAL

Abstract. The assumptions and basic equations of the first-order shear deformation plate theory of Mindlin, as one which provides more accurate solutions compared to the classical theory, are briefly presented in this paper. Application of one analytical solution derived according to this theory is presented by use of example of stress-state and deformations calculation of the reinforced concrete footing, which has been the object of recent author's experimental research. Numerical results obtained by applied procedure, which refer to the elastic domain of material behavior, are compared with experimentaly obtained data of deflections of footing plate midpoint. Key words: Mindlin's plate bending theory, deflection, rotation of cross section, internal forces, footing, soil slenderness. 1