The Prognostic Effect of Circadian Blood Pressure Pattern on Long-Term Cardiovascular Outcome is Independent of Left Ventricular Remodeling

We aimed to investigate the predictive value of 24 h blood pressure (BP) patterns on adverse cardiovascular (CV) outcome in the initially untreated hypertensive patients during long-term follow-up. This study included 533 initially untreated hypertensive patients who were involved in this study in the period between 2007 and 2012. All participants underwent laboratory analysis, 24 h BP monitoring, and echocardiographic examination at baseline. The patients were followed for a median period of nine years. The adverse outcome was defined as the hospitalization due to CV events (atrial fibrillation, myocardial infarction, myocardial revascularization, heart failure, stroke, or CV death). During the nine-year follow-up period, adverse CV events occurred in 85 hypertensive patients. Nighttime SBP, non-dipping BP pattern, LV hypertrophy (LVH), left atrial enlargement (LAE), and LV diastolic dysfunction (LV DD) were risk factors for occurrence of CV events. However, nighttime SBP, non-dipping BP pattern, LVH, and LV DD were the only independent predictors of CV events. When all four BP pattern were included in the model, non-dipping and reverse dipping BP patterns were associated with CV events, but only reverse-dipping BP pattern was independent predictor of CV events. The current study showed that reverse-dipping BP pattern was predictor of adverse CV events independently of nighttime SBP and LV remodeling during long-term follow-up. The assessment of BP patterns has very important role in the long-time prediction in hypertensive population

Relation between Kinetic Friction Coefficient and Angular Acceleration during Motion Initiated by Dynamic Impact Force

The paper presents theoretical and experimental analyses of the kinetic friction coefficient of a ball bearing in conditions of rotational motion initiated by dynamic impact force. A method has been developed and a measurement system allows the measurement of a kinetic coefficient of friction through the measurement of the angular acceleration. This paper considers the friction caused by rotational motion initiated by the force impact impulse. After the external force (impact impulse) stops acting, the motion continues, and the loaded bearing (i.e. the zone of the bearing in which the frictional resistance forces act) exhibits a broad spectrum of velocities, from the maximum value at the moment of motion initiation to the zero value when motion stops, where the whole measuring system acts as a rotary encoder. Experimental results indicate a high dependency between angular velocity and friction coefficient, similar to functional dependency. This paper proves that kinetic friction coefficient can be reliably measured using the measurements of angle change and angular velocity. Analysed method has high potential in the diagnostics of energy loss in the tribo-mechanical systems

The Influence of Vacuum Level on the Friction Force Acting on the Pneumatic Cylinder Sealing Ring

Presented in this paper are the results of measurement of friction force acting on the pneumatic cylinder sealing rings under high vacuum atmosphere. The investigations were conducted at relatively low levels of sliding speed of the sealing ring. Special device was constructed and implemented to facilitate this experiment. The results indicate the importance of the vacuum level on the friction force magnitude. Higher vacuum levels influence significant increase of friction force. Special phenomenon is the decreasing of friction force at higher sliding speeds of the sealing ring along the cylinder, under the constant vacuum level. Therefore, detailed examination of this phenomenon in the domain of high sliding speeds could yield interesting results

A Novel Method for Determination of Kinetic Friction Coefficient using Inclined Plane

Presented in this paper is the theoretical background for a novel method for determination of kinetic friction coefficient. The method is based on the equation of movement of a rigid body along an inclined plane and has not been previously discussed in literature. According to the theoretical results presented in this paper, mean kinetic friction coefficient can be determined based on the time it takes a rigid body to travel a distance along an inclined plane. Experimental results show that the mean kinetic friction coefficient increases with increasing mean sliding velocity, i.e. with decreasing sliding time. Increasing sliding velocity increases deviation of friction coefficients. This method also allows the determination of energy consumed due to friction along the travelled distance. Increasing mean kinetic friction coefficient and mean sliding velocity increases energy consumed due to friction. Practical calculation requires application of the distance law, which, in turn, requires accurate measurement of the sliding time and distance

Influence pressure and size particle to extraction by CO2

Supercritical fluid extraction (SFE) is an efficient extraction technique for the separation of various organic compounds from herbs, or more generally, from plant materials. These proporties of SFE make the products more advantageous in the field of foods, pharmaceuticals, and cosmetics. The aim of this study was to investigate the effect of pressure and particle size on the extraction yield and the quality of the extracts

Intelligent design and optimization of machining fixtures

U radu je predstavljen integralni sustav za projektiranje i optimizaciju konstrukcije naprava za strojnu obradu. Dio sustava za optimizaciju omogućuje, s jedne strane, određivanje optimalnih pozicija elemenata za baziranje i stezanje kako bi se postigla potrebna točnost i kvaliteta obrađene površine izratka, a s druge strane, generiranje konstrukcije naprava bez kolizija. Dio sustava za projektiranje osigurava izbor pojedinih elemenata naprava na osnovi prethodno definiranih produkcijskih pravila. Prilagođeni kriteriji izbora definirani su za elemente za baziranje, elemente za stezanje, elemente za vođenje alata, elemente za podešavanje položaja alata, elemente tijela naprava, elemente za povezivanje i nadogradne elemente. Sustav je baziran na geometrijskim karakteristikama i karakterističnim obilježjima djela, kao i dodatnim informacijama o obradi i informacijama iz tehnološkog procesa. Sustav je razvijan za operacije tokarenja, bušenja, glodanja i brušenja koje se izvode na rotacijskim i prizmatičnim radnim predmetima. U radu su djelomično prikazani izlazni rezultati razvijenog sustava. Na kraju rada dani su odgovarajući zaključci i istaknuti mogući pravci daljih istraživanja.This work presents an integral system for machining fixture layout design and optimization. The optimization module of this system allows determination of optimal positions of locating and clamping elements, which provides required accuracy and surface quality, while at the same time guarantees design of collision-free fixtures. The design module performs selection of required fixture elements based on a set of predefined production rules. Adequate criteria for the selection of fixture elements are defined for locating, clamping, tool guiding, and tool adjustment elements, as well as for fixture body elements, connecting elements and add-on elements. The system uses geometry and feature workpiece characteristics, as well as the additional machining, and process planning information. It has been developed to accommodate machining processes of turning, drilling, milling, and grinding of rotational and prismatic workpieces. A segment of output results is also shown. Finally, conclusions are presented with directions for future investigation

Increasing Stiffness of Constructions through Application of Enhancing Elements

Presented in this work is a study on construction stiffness, based on examination of their neutral lines for various cross-section geometries and different force magnitudes. Investigations were conducted both through numerical simulations and experimentally. The results of numerical simulations indicate that stiffness enhancement reduces deflection in the range of 41-52 %, while the experimental tests showed the reduction of 42-54 %. Also reviewed is comparative analysis between the stiffness results obtained by numerical analyses and experiments, which showed high degree of their compliance. The deviations between the results offered by the two methods are 1-3 %, on average, while in the worst case, which occurs in just a couple of points, the deviation equals 10 %. This study revealed significant increase of element stiffness, which was obtained by employment of additional stiffness enhancing elements

Analiza stanja i mogućnosti unapređenja proizvodnje strnih žita na teritoriji Gruže i Rudničke Morave

In the area which includes the territory of Gruža and Rudnička Morava agricultural production is the primary work activity of the local population where the grain crops grown on the largest area and production of cereals is present in all the areas of the village. In most of the color producers present the traditional approach in production. This mode of production often affects the achievement of lower average grain yield and low economic returns. Based on a comprehensive analysis of certain conditions it was found that in the short term will be to increase the area under small grains, and the application of modern production technologies increase the average grain yield. Also, in certain regions, where there are favorable conditions could be applied integral and organic vision of production, which would significantly contribute to achieving greater material benefit local populations and foster the accelerated development of the area.Na prostoru koji obuhvata teritorija Gruže i Rudničke Morave poljoprivredna proizvodnja predstavlja osnovnu radnu aktivnost lokalnog stanovništva pri čemu se strna žita gaje na najvećoj površini a proizvodnja žitarica je prisutna u atarima svih sela. Kod najvećeg boja proizvođača prisutan je tradicionalni pristup u proizvodnji. Ovaj način proizvodnje često utiče na postizanje prosečno nižih prinosa zrna i niske ekonomske dobiti. Na osnovu sveobuhvatne analize pojedinih uslova utvrđeno je da bi u kratkoročnom periodu mogle da se povećaju površine pod strnim žitima i da se primenom savremene tehnologije proizvodnje povećaju prosečni prinosi zrna. Takođe, u pojedinim regijama, gde postoje povoljni uslovi mogao bi da se primeni integralni i organski vid proizvodnje, čime bi se značajno doprinelo ostvarivanju veće materijalne dobiti lokalnog stanovništva i pospešio ubrzani razvoj područja

Biosynthesis of ZnO nanoparticles using agro-waste with antibacterial and antioxidant activity

Green synthesis is a more sustainable option using renewable biomass such as plants as reducing or stabilizing agents compared to toxic chemical compounds. These biological substances also behave as capping agents, which control the size and shape of the nanoparticles. In this work, ZnO nanoparticles (NPs) have been prepared via a simple, low cost and ecofriendly method using citrus fruit peel and extracts as biological reducing agents. Zinc nitrate and zinc acetate were used as a source of zinc ions.XRD analysis revealed the formation of a ZnO wurtzite phase without impurities. Synthesized ZnO NPs with an average electronic band gap ∼3 eV were obtained and found to have round-like, hexagonal-like or needle-like structures depending on precursor type. EDS analysis showed a homogeoneous distribution in Zn and O elements, attributed to single-phase ZnO constituents. Antibacterial and antioxidant activities of synthesized NPs were evaluated. Obtained results showed that ZnO synthesized from nitrate precursors are more effective in inhibiting growth of Salmonella and Staphylococcus Aureus. Antioxidant activity of ZnO NPs determined using CUPRAC and ABTS assays showed higher activity of ZnO obtained using nitrate precursors. The maximum scavenging activity of 90% was observed at the concentration of 10 mg/m

Modelling and enhancement of organizational resilience potential in process industry SMEs

The business environment is rapidly changing and puts pressure on enterprises to find effective ways to survive and develop. Since it is almost impossible to identify the multitude of complex conditions and business risks, an organization has to build its resilience in order to be able to overcome issues and achieve long term sustainability. This paper contributes by establishing a two-step model for assessment and enhancement of organizational resilience potential oriented towards Small and Medium Enterprises (SMEs) in the process industry. Using a dynamic modelling technique and statistical tools, a sample of 120 SMEs in Serbia has been developed as a testing base, and one randomly selected enterprise was used for model testing and verification. Uncertainties regarding the relative importance of organizational resilience potential factors (ORPFs) and their value at each level of business are described by pre-defined linguistic expressions. The calculation of the relative importance of ORPFs for each business level is stated as a fuzzy group decision making problem. First, the weighted ORPFs’ values and resilience potential at each business level are determined. In the second step, near optimal enhancement of ORPFs’ values is achieved by applying a genetic algorithm (GA).Research presented in this paper was supported by Ministry of Science and Technological Development of Republic of Serbia, Grant No 35033, Title: Sustainable development technology and equipment for the recycling of motor vehicles.info:eu-repo/semantics/publishedVersio