Numerical study of smoke flow control in tunnel fires using ventilation systems

Sa ciljem procenjivanja mogućnosti jednog tunelskog ventilacionog sistema, da u incidentnom radnom režimu kontroliše širenje dima i da tako obezbedi uslove za bezbednu evakuaciju ljudi iz vatrom zahvaćenog prostora, izvršena je CFD (Computational Fluid Dynamics) simulacija požara u jednom dvocevnom tunelu. Korišćenjem eksperimentalnih rezultata, o dinamici sagorevanja zapaljenog automobila i prema preporukama PIRAC-a određenih radnih režima ventilatora, izvršena je provera kritične brzina strujanja vazduha kojom će se sprečiti prodor dima u evakuacione hodnike, te izvršena provera potrebnog broja i rasporeda ventilatora u tunelskim cevima.With the aim of evaluating capabilities of a tunnel ventilation system to control the spread of smoke in the emergency operating mode, thereby providing conditions for safe evacuation of people from a fire-struck area, a CFD (Computational Fluid Dynamics) simulation of a fire in a double tube tunnel was done. By the use of experimental results regarding the combustion dynamics of a passenger car, that is truck on fire and ventilation system operating modes determined according to PIRAC recommendations, a check of critical air velocity required to prevent smoke penetration into the evacuation hallways was performed, as well as the check of the optimum number and positions of ventilators in the tunnel tubes

Numerical study of smoke flow control in tunnel fires using ventilation systems

Sa ciljem procenjivanja mogućnosti jednog tunelskog ventilacionog sistema, da u incidentnom radnom režimu kontroliše širenje dima i da tako obezbedi uslove za bezbednu evakuaciju ljudi iz vatrom zahvaćenog prostora, izvršena je CFD (Computational Fluid Dynamics) simulacija požara u jednom dvocevnom tunelu. Korišćenjem eksperimentalnih rezultata, o dinamici sagorevanja zapaljenog automobila i prema preporukama PIRAC-a određenih radnih režima ventilatora, izvršena je provera kritične brzina strujanja vazduha kojom će se sprečiti prodor dima u evakuacione hodnike, te izvršena provera potrebnog broja i rasporeda ventilatora u tunelskim cevima.With the aim of evaluating capabilities of a tunnel ventilation system to control the spread of smoke in the emergency operating mode, thereby providing conditions for safe evacuation of people from a fire-struck area, a CFD (Computational Fluid Dynamics) simulation of a fire in a double tube tunnel was done. By the use of experimental results regarding the combustion dynamics of a passenger car, that is truck on fire and ventilation system operating modes determined according to PIRAC recommendations, a check of critical air velocity required to prevent smoke penetration into the evacuation hallways was performed, as well as the check of the optimum number and positions of ventilators in the tunnel tubes

Computational study of smoke flow control in garage fires and optimization of the ventilation system

With the aim of evaluating capabilities of a ventilation system to control the spread of smoke in the emergency operating mode, thereby providing conditions for safe evacuation of people from a fire-struck area, computational fluid dynamics simulation of a fire in a semi-bedded garage was conducted. Using the experimental results of combustion dynamics of a passenger car on fire, optimal positions of ventilation openings were determined. According to recommendations by DIN EN 12101 standard, the operating modes of a ventilation system were verified and optimal start time of the smoke extraction system was defined

The alternative energy sources review

Renewable energy sources are energy sources that are derived from nature and can be renewed. Today, they are increasingly being used because of their harmlessness to the environment. Most renewable energy technologies are powered directly or indirectly from the Sun. The composition of the Earth’s atmosphere is balanced, so that the radiation into space is equal to the μmincoming solar radiation, which results in a certain energy degree within the Earth’s atmosphericcomposition, and we can roughly describe it as the Earth’s climate. Renewable energy is obtained from natural processes that are constantly renewed. In its various forms, it derives directly from the sun, or from heat generated deep within the Earth. It also includes electricity and heat generated from sources such as sunlight, wind, oceans, hydropower, biomass and geothermal energy, biofuels and hydrogen from renewable sources. Each of these sources has unique characteristics that influence how and where they can be used. Renewable energy sources include: solar energy, wind energy, biomass, biofuel, biogas, geothermal sources, energy of small watercourses, tidal energy, energy of the waves, internal energy of the sea and the ocean

The contribution of football elements to the efficiency of teaching physical education for preschool children

Predmet ovog istraživanja su motorička znanja,morfološke karakteristike i aktivno vreme na času fizičkog vaspitanja kod dece predškolskog uzrasta, muškog pola,starosti 6 godina((±3 meseca). Primarni cilj istraživanja je bio da se ispita uticaj inoviranog programa koji u sebi sadrži elemente fudbala na motorička znanja kod dece predškolskog uzrasta u odnosu na standardni program, koliko takav program doprinosi da deca budu aktivna na času fizičkog vaspitanja, kao i na koje varijable kod primenjene baterije testova ovaj program ima najveći uticaj. Ovo istraživanje realizovano je kao empirijsko istraživanje longitudinalnog tipa. Korišćen je kvazi-eksperimentalni dizajn sa dva odeljenja dece predškolskog uzrasta PU ,, Čika Jova Zmaj“ iz Pirota podeljeni kao eksperimentalna i kontrolna grupa. Standardni program fizičkog vaspitanja i eksperimentalni program iz fudbala realizovani su u toku 12 nedelja, sa ukupno 36 časa fizičkog vaspitanja odnosno treninga. Baterijom testova procenjen je nivo bazičnih motoričkih znanja za savladavanje prostora, bazičnih motoričkih znanja za manipulisanje objektima i aktivno vreme na časovima fizičkog vaspitanja i treninga kod dece predškolskog uzrasta i to u dve vremenske tačke- kao inicijalno i finalno merenje. Dobijeni rezultati istraživanja su pokazali da je eksperimentalni tretman iz fudbala u globalu pozitivno uticao na razvoj bazičnih motoričkih znanja za savladavanje prostora i manipulisanje objektima eksperimentalne grupe dece predškolskog uzrasta u odnosu na kontrolnu grupu koja je imala standarnu nastavu fizičkog vaspitanja, dok su se posebne razlike ogledale u testu skok u dalj. Sam eksperimentalni tretman na kraju je doveo i do poboljšanja rezultata u testovima skok u dalj, udaranje lopte koja miruje i udarac lopte nogom kod eksperimentalne grupe, dok su se razlike u efektima eksperimentalnog tretmana ogledale kod testa skok u dalj, preskakanje, galop strance i udaranje lopte koja miruje kod eksperimentalne grupe. Rezultati ovog istraživanja su pružili nova saznanja i informacije o mogućnosti primene i uticaja elemenata fudbalske igre u nastavi kod dece predškolskog uzrasta

Increasing the energy efficiency of small hydropower plants

REZIME: U disertaciji su analizirane mogućnosti povećanja energetske efikasnosti malih hidroelektrana. Fokus je na rešavanju problema: (i) niske efikasnosti proizvodnje električne energije pri protocima koji su manji od granice do koje proizvođač garantuje efikasnost turbine i (ii) neefikasnog izdvajanja sedimenata usled nejednakih protoka kroz komore višekomornih taložnika. Drugi problem se rešava originalnom metodologijom, koja predstavlja nadgradnju tradicionalnog korišćenja CFD i analitičkih modela. U njenoj primeni leži najveći naučni doprinos, u koji spadaju: metoda iterativnog traženja optimalnog tehničkog rešenja korišćenjem CFD i pomoćnog analitičkog modela, koji služi kao vodilja složenog i tromog modela ka optimalnoj geometriji, metoda određivanja lokalnih otpora složenih geometrijskih oblika sa višedimenzionalnom strujnom slikom korišćenjem CFD simulacija, regresione analize i posredne validacije, primena savremenih računarskih alata na projektovanje, optimizaciju, modeliranje i rekonstrukciju MHE, i originalno rešenje za istovremeno izjednačavanje i umirenje protoka u ulaznoj zoni višekomornih taložnika. Nabrojani rezultati su primenjeni na dve elektrane sa instalisanim snagama 1,220 MW i 1,327 MW, koje rade u linijski spregnutom sistemu sa zajedničkim vodozahvatom, i rezultirale su tehničkim rešenjima za: određivanje optimalne konfiguracije pri postojećim uslovima (bruto pad, turbine, prečnici cevovoda) korišćenjem nove(ih) turbina i nezavisnog ili spregnutog rada kaskadnih derivacionih MHE-a, izjednačavanje protoka i umirenje struja (prigušenje turbulencija) ugradnjom usmerivača u ulaznoj zoni višekomornih taložnika, i izjednačavanje protoka i umirenje struja korišćenjem tablastih zatvarača i umirujućih šipki na ulazima komora taložnika. Rešavanjem (i) problema povećana je EE obe elektrane za 4.8%, dok se rešavanjem (ii) problema smanjuju gubici nastali u eksploataciji za 8%. Rezultati disertacije su primenjivi na svim postojećim i novoprojektovanim MHE-ma sa bočnim vodozahvatima, dok predložene metodologije prevazilaze oblast MHEa.ABSTRACT: The core of the dissertation is to improve energy efficiency of small hydropower plants (SHPPs). The focus is to solve the problems of (1) decreased electricity production during low water flows and (2) inadequate functioning of multi-chamber settling basins because of an uneven flow distribution among the chambers. The latter problem has been solved by an original methodology, which is an upgrade on the traditional usage of CFD and analytical models. The methodology is among the scientific contributions that are: a method for the iterative finding of a technical solution by the use of a CFD and an ancillary analytical model, which is a guide for a complex and slow CFD model towards an optimal geometry; a method for the determination of local pressure drops (minor losses) for complex geometrical shapes with multi-dimensional flow patterns using: CFD simulations, regression analysis, and indirect validation; the application of modern software for the design, optimization, modeling, and modernization of SHHPs. a novel solution for simultaneous equalization of flows among the chambers of a multi-chamber settling basin and the dissipation of turbulent kinetic energy. These results were implemented on a case study, which includes two cascade SHPPs with a common side water intake and nominal installed capacities of 1.220 MW and 1.327 MW. The solving of both problems resulted in technical solutions for: the determination of an optimal configuration under existing conditions (gross head, turbine types, pipeline diameters) by the use of new turbine(s) and independent or coupled operation of two run-of-the-river SHPPs; the equalization of flows among the chambers of a multi-chamber settling basin and the dissipation of turbulent kinetic energy by the use of: (a) pillars with vanes in a common inlet zone and (b) sluice gates with tranquilizing racks. The solution of the (1) problem increased the electricity production by 4.8% and the solution of the (2) problem reduced the total loss by 8%. The results are applicable to all new and existing SHPPs with side water intakes, whereas the developed methodologies exceed the field of SHPPs

Penicillin-induced cutaneous necrotizing eosinophilic vasculitis with cryofibrinogenemia

Cutaneous necrotizing eosinophilic vasculitis (CNEV) is a rare type of vasculitis. Eosinophilic vasculitis is a necrotizing vasculitis with eosinophilic vascular infiltration, in which eosinophils mediate vascular damage in the disease process. We present a case of an 18-year-old girl who developed palpable purpura and hemorrhagic bullae over the lower extremities associated with itching, 7 days after the commencement of penicillin therapy. Plasma cryofibrinogen was positive. Histopathology showed an infiltration of eosinophils within and around the vessel walls and a complete absence of nuclear dust and neutrophils. Oral prednisone at 1 mg/kg induced remission in 2 weeks; the prednisone dose was tapered and discontinued after 2.5 months. There was no evidence of recurrence after 37 months of follow-up. Our patient represents a rare case of drug/penicillin-induced CNEV associated with cryofibrinogenemia, without systemic organ involvement. , and histopathological features of the lesion. Moreover, the possible complications of surgical approaches, namely healing defects, failure of skin grafts, and wound infection, should be considered. In this review we discuss the management of BCC localized on the face and scalp, according to the currently available treatment options.  </p

MEDICAL NUTRITION THERAPY IN MANAGEMENT OF EATING DISORDERS

The treatment of eating disorders demands a comprehensive medical approach, where a dietitian has an important role, primarily due to numerous instances of malnutrition. The objective of this paper was to recapitulate the research findings and clinical evidence which show the importance of medical nutrition therapy in the treatment of eating disorders; furthermore, they present significant guidelines for clinical practice. The research methods have entailed a thorough exploration of literature available at research data bases. The results of the research studies published so far have unambiguously pointed out that, when eating disorders are concerned, there is an urgent need for a diet therapy in order for the patient to restore the appropriate body weight as well as normal eating habits. On the one hand, certain authors suggest returning to normal nutritional habits immediately, whereas, on the other hand, certain others advocate a diet therapy program, that is, a gradual process of recovery. Patients incapable of oral food intake receive enteral nutrition. Parenteral nutrition is applied for recovering the lost electrolytes and fluids, but it should be applied rarely, primarily in states of urgency. For patients suffering from eating disorders the increase in weight indicates good chances of recovery; therefore, the patient’s nutritional status should be carefully and continuously noted. Finally, it is important that our country, too, should adopt a carefully prescribed and conducted diet therapy as an obligatory step in the treatment of patients with eating disorders

Biological activity of essential oils of selected aromatic plants on species of the genera Staphylococcus, Streptococcus, Lactobacillus, Pseudomonas, Enterococcus and Candida isolated from the human oral cavity

Oralno zdravlje smatra se važnim delom opšteg zdravlja ljudi, ali je često zanemarena oblast, a razlozi tome su raznovrsni i kompleksni. Visoka učestalost oralnih oboljenja ima veliki socijalni i ekonomski uticaj. Najčešća oboljenja usne duplje su karijes, parodontalna oboljenja i oralne infekcije, dok su glavni uzročnici ovih oboljenja vrste rodova Streptococcus mutans-grupa, Staphylococcus, Lactobacillus, Pseudomonas, Enterococcus i Candida. Efikasan tretman i razvoj novih antiseptika koji poseduju antimikrobnu aktivnost je od velikog značaja za medicinu. Najčešće se koriste preparati koji sadrže hlorheksidin, povidon jod i cetilpiridinijum hlorid, zatim sintetička sredstva kao što su penicilin, cefalosporini, tetraciklini i njihovi derivati, nistatin, amfoterecin B, flukonazol itd. Ovi agensi poseduju antimikrobno dejstvo i kontrolišu upalu desni, ali imaju ograničenu efikasnost i veliki broj negativnih posledica kao što su bojenja zuba, iritacije sluzokože usne duplje, pojave alergije, nefrotoksičnost i endokrinu toksičnost, a povezuju se i sa kancerom i drugim sekundarnim oboljenjima. Problem rezistencije prema Svetskoj zdravstvenoj organizaciji je najveća pretnja globalnom zdravlju čoveka. Jedna od alternativa koja je poslednjih decenija u žiži naučnih interesovanja jesu etarska ulja kao izvor biološki aktivnih jedinjenja. U cilju dobijanja novih biološkli aktivnih jedinjenja, koja neće biti toksična za humane i animalne ćelije, u ovoj disertaciji analiziran je hemijski sastav i biološka aktivnost in vitro 60 komercijalnih uzoraka etarskih ulja ekstrahovano iz 47 biljnih vrsta: Cananga odorata, Foeniculum vulgare, Pimpinella anisum, Pastinaca sativa, Anethum graveolens, Matricaria recutita, Achillea millefolium, Helichrysum italicum, Boswellia carterii, Canarium luzonicum, Commiphora myrrha, Juniperus communis, J. virginiana, Gaultheria procumbens, G. fragrantissima, Pelargonium graveolens, Hyssopus officinalis, Mentha piperita, M. pulegium, Lavandula angustifolia, Thymus algeriensis, T. vulgaris, T. serpyllum, Rosmarinus officinalis, Salvia lavanudilifolia, S. officinalis, S. sclarea, S. triloba, Satureja montana, Laurus nobilis, Leptospermum petersonii, L. scoparium, Eucalyptus citriodora, E. globulus, Melaleuca alternifolia, M. quinquenervia, Syzygium aromaticum, Abies procera, A. grandis, A. alba, Pseudotsuga douglasii, Pinus silvestris, Piper nigrum, Cymbopogon martinii, Rosa centifolia, Citrus aurantium spp. aurantium i C.limon. Cilj rada je ispitivanje biološke aktivnosti i uticaja etarskih ulja i komponenti odabranih aromatičnih biljaka na mikroorganizme izolovane iz usne duplje čoveka i primena u prevenciji i lečenju oralnih bolesti i infekcija...Oral health is considered an important part of general health, but is often neglected area, and the reasons for this are diverse and complex. The high incidence of oral disease has a huge social and economic impact. The most common diseases of the oral cavity are dental caries, periodontal disease, and oral infections, while the main causal agents of these diseases are species of genus Streptococcus mutans-group, Staphylococcus, Lactobacillus, Pseudomonas, Enterococcus and Candida. Effective treatment and developing new drugs that have antimicrobial activity is of great significance for medicine. The most commonly used preparations containing chlorhexidine, povidone iodine and cetylpyridinium chloride, followed by synthetic drugs such as penicillin, cephalosporins, tetracyclines and their derivatives, nystatin, amphotericin B, fluconazole, etc. These agents possess antimicrobial activity and control gum inflammation, but have limited efficacy and a large number of negative effects such as tooth staining, mucosal irritation, allergy, nephrotoxicity and endocrine toxicity, and are also associated with cancer and other secondary illnesses. The problem of resistance to the World Health Organization is the biggest threat to global human health. One of the alternatives that in recent decades are in focus of scientific interest are essential oils as a source of biologically active compounds. In order to obtain new biologically active compounds, which will not be toxic to human and animal cells, in this dissertation analysis of the chemical composition and biological activity in vitro of 60 commercial samples of essential oils extracted from 47 plant species were used: Cananga odorata, Foeniculum vulgare, Pimpinella anisum, Pastinaca sativa, Anethum graveolens, Matricaria recutita, Achillea millefolium, Helichrysum italicum, Boswellia carterii, Canarium luzonicum, Commiphora myrrha, Juniperus communis, J. virginiana, G . fragrantissima, Pelargonium graveolens, Hyssopus officinalis, Mentha piperita, M. pulegium, Lavandula angustifolia, Thymus algeriensis, T. vulgaris, T. serpyllum, Rosmarinus officinalis, Salvia lavanudilifolia, S. officinalis, S. sclarea, S. triloba, Satureja montana, Laurus nobilis, Leptospermum petersonii, L. scoparium, Eucalyptus citriodora, E. globulus, Melaleuca alternifolia, M. quinquenervia, Syzygium aromaticum, Abies procera, A. grandis, A. alba, Pseudotsuga douglasii, Pinus silvestris, Piper nigrum, Cymbopogon martinii, Rosa centifolia, Citrus aurantium spp. aurantium and C. limon..