The exact analytical solution for the gas lubricated bearing in the slip and continuum flow regime

The exact analytical solution for the compressible two-dimensional gas flow in the microbearing is presented. The general slip-corrected Reynolds lubrication equation is derived and it is shown that it possesses an exact analytical solution. It is obtained by a suitable transformation of the independent variable, and it provides the pressure distribution in the bearing as well as the mass flow rate through it. By neglecting the rarefaction effect, this solution is also applicable to the continuum gas flow in the bearing, which also does not exist in the open literature. The obtained analytical solution can be usefully applied for testing the other, experimental or numerical results

An exact analytical solution for the second order slip-corrected Reynolds lubrication equation

Izvedena je opšta Rejnoldsova jednačina podmazivanja za uslove strujanja sa klizanjem primenom opštih graničnih uslova klizanja drugog reda i pokazano je da ona ima tačno analitičko rešenje. Rešenje je dobijeno tansformacijom zavisno promenljive što je dovelo do mogućnosti analitičkog proračuna raspodele pritiska i masenog protoka u mikroležaju. Na taj način, poređenjem sa datim analitičkim rešenjem omogućena je provera eksperimentalnih i numeričkih rezultata za strujanje gasa u mikroležajima.We derive a general slip-corrected compressible Reynolds lubrication equation, valid for any choice of the slip velocities, and show that it possesses the exact analytical solution. It is obtained by a suitable transformation of the dependent variable, and it yields both the pressure distribution in the bearing and the mass flow rate through it. It can be usefully applied for testing the other, experimental or numerical results obtained under the same or similar physical conditions, against this solution

An exact analytical solution for the second order slip-corrected Reynolds lubrication equation

Izvedena je opšta Rejnoldsova jednačina podmazivanja za uslove strujanja sa klizanjem primenom opštih graničnih uslova klizanja drugog reda i pokazano je da ona ima tačno analitičko rešenje. Rešenje je dobijeno tansformacijom zavisno promenljive što je dovelo do mogućnosti analitičkog proračuna raspodele pritiska i masenog protoka u mikroležaju. Na taj način, poređenjem sa datim analitičkim rešenjem omogućena je provera eksperimentalnih i numeričkih rezultata za strujanje gasa u mikroležajima.We derive a general slip-corrected compressible Reynolds lubrication equation, valid for any choice of the slip velocities, and show that it possesses the exact analytical solution. It is obtained by a suitable transformation of the dependent variable, and it yields both the pressure distribution in the bearing and the mass flow rate through it. It can be usefully applied for testing the other, experimental or numerical results obtained under the same or similar physical conditions, against this solution

Comparative analyses of built environment exposures relevant to health of greenhouse gas emissions reduction strategies in Serbia

Paper presents comparative analysis of residential indoor air pollutant concentration change over future specified time horizon, implementing building physical and thermal retrofit measures, thus creating pollution mitigation scenarios for existing Belgrade and Nis housing stock followed by greenhouse gas emission reduction scenarios up to 2050. Regarding specified mitigation scenarios, the set of typical housing unit models has been generated which define existing housing stock of Belgrade and Nis. Extensive monitoring of physical and thermal parameters as well as detailed socio-technical survey of selected households was performed and used as an initial modeling input. Relationship between environment pollution and building performances was investigated, with respect to indoor-outdoor sources of pollution, thermal and physical properties of the stock samples and occupant's behavior. As a final output, indoor pollutant concentrations for each of the modelled cases was obtained and validated against the available data. This housing modelling framework has been created in order to develop an assessment of present and future exposure and health impact quantity regarding single/multiple scenario interventions introduced to the housing stock. This paper provides each strategy guidelines for taking measures towards achieving the healthier indoor environments

Ecoclimatic and balneological features of spa settlements in Juzna Morava basin as function of sustainable development

Познавање климатских, биоклиматских и балнеолошких референци значајно је за познавање лечилишних и рекреативно-терапеутских вредности бањских и климатских места. У том контексту сматрамо важним истаћи и утицај планетарних климатских промена на екоклиматске и биоклиматске вредности бањско-климатских места, као важних лечилишних, рекреативних и еколошких дестинација. У подручју слива Јужне Мораве налази се 10 афирмисаних бањских насеља: Бујановачка Бања, Врањска Бања, Сијеринска Бања, Пролом Бања, Куршумлијска Бања, Луковска Бања, Рибарска Бања, Сокобања, Нишка Бања и Звоначка Бања. Ни једна од ових бања нема квалитетно обрађене и комплетне био-климатске анализе, те је било неопходно приступити изради озбиљних климатско-биоклиматских анализа у којима би се, поред балнеолошке слике, презентирала лечилишно-терапеутско- рекреативна могућност наведених бањских места. Истраживања физичко-географских карактеристика имају задатак да одговоре на основне природне предиспозиције које су условиле термоминералне појаве, што је била полазна основа за формирање бањских места која су се с временом развила у бањска насеља. У питању је утврђивање природних потенцијала, њихове валоризације, водећи рачуна о правилном управљању и заштити човекове животне средине. Постојеће информације у проспектима о бањама су неодређене и нестручне, па се о појединим бањама говори као о местима која имају ,,здрав планински ваздух", ,,специфичну ружу ветрова У циљу комлетирања слике потенцијалности наведених бањаских места изнеће се анализа екоклиматских и балнеолошких карактеристика и ставити у функцију и планирања и развоја датих места, која су се временом трансформисала у насеља. То подразумева и анализу климатских елемената и комплексних климатских веза. У раду су анализирати климатски елементи: температура ваздуха, влажност ваздуха, ваздушни притисак, ветар, облачност и трајање сунчевог сјаја, како би се схватиле основне карактеристике климе ових места...An insight into climatic, bioclimatic and balneological references is crucial to understanding healing and recreationally therapeutic spa and climatic place values. In the context given, it is important to emphasise the influence of global climatic changes on the eco climatic and bioclimatic values of spa climatic places as important healing, recreational and ecological destinations. There are ten formed spa settlements within the Juzna Morava Basin, which includes Bujanovacka Banja, Vranska Banja, Sijerinska Banja, Prolom Banja, Kursumlijska Banja, Lukovska Banja, Ribarska Banja, Sokobanja, Niska Banja and Zvonacka Banja. None of the spas has completely viewed bioclimatic analyses; therefore, it was of crucial importance to initiate the foundation of relevant bioclimatic analyses, in which, apart from a balneological image, the healing and therapeutaically recreational capacity of the places would be presented. The exploration of physically geographical features aims at answering the basic natural prerequisites that have caused thermo mineral phenomena, which has formed the basis for the formation of spas ,which over time have grown into settlements. This determines natural potentials, including their valorization, minding the course of correct management and environmental protection. The current information concerning spa prospects has been imprecise and unprofessional. Therefore, particular spas have been referred to as having healthy mountainous air or a specific wind source. In an attempt to complete the picture of the given spas potential, what is being exposed is the analysis of eco climatic and balneological features, its planning function, as well as the development of the places, which in time have become settlements. This entails a climatic element analysis and complex climatic relations. The work has analysed climatic elements : air temperature, air humidity, air pressure, winds , cloudiness and the permanance of sun rays in order to realise the basic climatic features of the places. What follows is the analysis of a complex climatic relation as to determine the basic climatic types, bio types and classes..

Correlation Between Morphology and Structure of Galvanostatically Electrodeposited Tin Dendrites

Tin dendrites found wide application in various industries.1 They can be obtained by both non-electrochemical and electrochemical methods of synthesis. In this study, they were produced by a galvanostatic regime of electrolysis from alkaline hydroxide solution at a current density of –3 mA cm–2 , 1.5 times larger than the limiting diffusion current density, with an amount of the electricity of 200 and 400 mC. In the dependence of an amount of the passed electricity, Sn dendrites of various morphology and crystal orientation were obtained: the fern-like dendrites predominantly oriented in (220), (440) crystal planes are obtained with 200 mC and the spear-like and the dendrites with prismatic branches showing the strong (200),(400) preferred orientationwere obtained with 400 mC. The strong correlation between morphology and structure of Sn dendrites is established and it can be explained by analysis of chronopotentiometry response obtained at the given current density and by morphological and structural analyses of Sn dendrites obtained by a potentiostatic regime at cathodic potentials corresponding to values attained after the passed amount of the electricity of 200 and 400 mC. The chronopotentiometry response after spent 200 mC was dominantly in the (–1600 – 1740) mV vs. Ag/AgCl range, and the fern-like dendrites with the strong (220), (440) preferred orientation were obtained in this potential range. After spent 400 mC, the chronopotentiometry response was about –1200 mV vs. Ag/AgCl, and the spear-like and the dendrites with prismatic branches with the strong (200),(400) preferred orientationwere obtained at this cathodic potential

Fractal tools in terrorist and financial crime prevention

Information society imposes globalization and universality of values. In these circumstances, terrorism, institutional political violence which targets trying to achieve the morbid fear of provoking a spectacular way, inappropriately given conditions, becomes a real threat not only to the nations but also to politics on the global level. In 1996, the International Monetary Fund estimated that 2–5% of the worldwide global economy involved laundered money. Today, intelligence activities in preventing and combating terrorism include financial investigations and money laundering for the purpose of financing terrorism, resulting in broadening of the scope of data to the level which makes it impossible for human logical evaluation. Technologies development that enables increasing capacity of speed and the amount of data processing has enabled defining, analyzing and exploring more and more models. This led to the idea of computer experiments and simulations trying to get to more complex planning and forecasting for the purpose of countering terrorism and “dirty” money transaction, as highly dangerous, complex and variable phenomena. This presentation aims at quotation the wide spectrum of mathematically founded fractal concepts suited to generate computer models of anti-terrorist activities. In this sense, the logistic behind the items connected with detecting and recognizing degree of terroristic threat by comparing fractal structure of people’s faces, fast search through the databases of faces and fingerprints. The speed of searching processes is of vital importance which promotes the crucial importance of compression and data reduction with preservation of regularity. Especially important are analytic forecasting of missing visual data and forms, to supplement the empirical evidences and records. All these operations are possible with higher degree of knowledge utilization and adaptation of virtual reality in the fight against terrorism and different forms of money laundering. The results indicate that the achievements implementation of the concept of fractals depends on substantial prior knowledge, environmental influences, subsystem integration, decentralization and synchronization, and allows us to come up with similar high information technology models, but not necessarily to enable identification of the authentic features of the various anomalies that result in objectively a social consequences. In this sense, we conclude that the application of information technology in the fight against terrorism, based on the concept of fractals has its place in the arsenal of anti-terroristic prevention

Tvrdoća vode za piće kao faktor rizika za ishemijsku bolest srca

Prevalence of the ischemic heart disease (IHD) differs between populations of different countries. Also, amongst the population in a single country there are geographical variations in the incidence of IHD. If we exclude the unchanging risk factors for cardiovascular disease, a major changeable risk factors such a smoking, high blood pressure, increased cholesterol levels (total and LDL), diabetes mellitus, have so far not adequately explained the geographical variation in incidence of IHD. The existence of areas with high risk for IHD, especially for acute myocardial infarction, indicate that is very likely that environmental factors are also involved in the pathogenesis of the cardiovascular disease, and it is necessary to consider them carefully. In the last five decades epidemiological data have been accumulating on the protective effect of high values of hardness and Ca and Mg from drinking water on morbidity and mortality from cardiovascular disease. The aim of the study was to determine the interdependence between of hardness of drinking water, as well the risk factor and morbidity from ischemic heart disease. The study presents an epidemiological and ecological (correlation) study, within which a prospective analytical (anamnestic) small-scale study was performed. The research is based on the analyses of water hardness and the content of Ca and Mg in the drinking water of the Nis water supply system (NIVOS). As a source of data for IHD in the territory of Nis district, the relevant section of the National population register of acute coronary syndrome (REAKS) referring to the Nis district was used. The crude and standardized incidence rates (per specific gender and age) in the territorial units of Nis district formed on the basis of different hardness values of drinking water were calculated. A spatial distribution (map) of the average total crude incidence rate of IHD in the reporting period 2010-2012 was produced as well. As part of the anamnestic study, through interviews and using the original structured epidemiological questionnaire, information has been collected on how to enter drinking water and risk factors for IHD (smoking, physical activity, hereditary burden of heart disease and diabetes) in 200 subjects with territorial units in which the highest and lowest values of the hardness of drinking water and the contents of Ca and Mg. To determine the average daily energy intake (which includes the daily intake of fat, protein and carbohydrates), as well as the intake of Mg and Ca in patients, we used the validated semi-quantitative questionnaire on the frequency of food intake in the previous year, Food Frequency Questionnaire (FFQ). Testing of the nutritional status of subjects was carried out by measuring the anthropometric parameters (height, weight) using standard procedures to determine body mass index (BMI) as the ratio of body weight in kilograms by height squared in meters (kg / m2). Having reviewed the medical records of patients, data was collected on blood cholesterol, triglycerides and LDL cholesterol levels, and systolic and diastolic blood pressure. Research has shown that subjects who consumed soft and medium soft water for drinking (area Niska Banja) for over 10 years had a significantly higher incidence rate of IHD compared to people of the same sex and age who consume hard drinking water (villagers connected to the Moravian-part of the water supply system NIVOS). Although the daily intake of drinking water in the subjects was on average less than 2 l, using an amnestic study it was found that a negative correlation between Ca and Mg from drinking water and its hardness with IHD and risk factors for IHD existed: elevated triglycerides, total and LDL cholesterol, systolic and diastolic blood pressure. This survey also confirmed low intake of Ca and Mg in the food as risk factors for IHD as well as known risk factors for cardiovascular disease: a hereditary predisposition to heart disease, smoking and fat intake. Using a binary logistic regression analysis it was shown that the greatest influence on the occurrence of IHD, out of all investigated risk factors, is due to the magnesium from water (equivalent to Ca from the water - a protective factor, p = 0.000), magnesium from food (protective factor, p = 0.000) and fat (factor risk, p = 0.000). From the aspect of prevention of IHD, the ROC analysis determined that it is necessary to add per day for at least 75 mg of Ca and Mg 7 mg though drinking water and 802 mg of calcium and 260 mg of Mg though food intake. The results of this study suggest that the degree of hardness of drinking water in the central water supply systems should increase to the optimal 180dH- 200dH. Legislating water hardness, Ca and Mg in the regular assessments of drinking water would lead to an overall reduction of morbidity and mortality from cardiovascular disease

Ponašanje spregnutih nosača tipa drvo-beton izvedenih mehaničkim spojnim sredstvima pri eksploatacionom i graničnom opterećenju

U okviru ove disertacije prikazana su teorijska i eksperimentalna istraživanja u oblasti spregnutih nosača od drveta i betona. Eksperimentalnim istraživanjima obuhvaćene su tri međusobno povezane grupe ispitivanja: - ispitivanje fizičkih i mehaničkih karakteristika materijala ugrađenih u spregnute nosače drvo-beton (drvo, beton, sredstva za sprezanje); - određivanje modula pomerljivosti između drveta i betona za različite tipove veza, odnosno sprezanja; - ispitiyanje spregnutih nosača drvo-beton izvedenih različitim tipovima mehaničkih spojnih sredstava. Cilj ispitivanja bio je praćenje ponašanja spregnutih nosača pri eksploatacionom i graničnom opterećenju, odnosno, utvrđivanje njihovog naponskog i deformacijskog stanja za različite faze opterećenja sve do loma. U tu svrhu ispitano je osam spregnutih nosača sistema proste grede, raspona 4,0 m, sa armiranobetonskom pločom (b/d=60/7 cm) i gredom od lepljenog lameliranog drveta (b/h= 10/20 cm). Međusobna veza betonske ploče i drvene grede ostvarena je mehaničkim spojnim sredstvima (ekserima E50/150 i zavrtnjima фЮ/150) sa četiri načina (tipa) veze drvo-beton. Ispitivanje je izvršeno u posebnom čeličnom ramu, opterećenje je nanošeno hidrauličkom presom, a deformacije su merene ugibomerima i memim trakama. Prikazano je i eksperimentalno određivanje modula pomerljivosti za primenjene tipove veza i dat predlog modela za njegovo ispitivanje. Pored eksperimentalnog istraživanja data je i analitička metoda proračuna po teoriji elastičnog sprezanja, kao i numerička analiza nosača primenom metode konačnih elemenata i poređenje dobijenih rezultata. Prikazan je pregled dosadašnjih teorijsko-eksperimentalnih istraživanja u oblasti sprezanja drveta i betona, kao i primena spregnutih nosača u konstrukcijama mostova, stambenih i drugih objekata. Rad rezultira preporukama za osavremenjavanje važeće tehničke regulative iz oblasti drvenih i spregnutih konstrukcija, a saglasno izrazitoj aktuelnosti i strucnoj opravdanosti tematike, prezentirani su i mogući pravci za dalji naučno-istraživački rad u ovoj oblasti.The dissertation presents theoretical and experimental research of composite wood and concrete beams. Experimental study comprise three inter-related groups of investigation: - physical and mechanical characteristics of built-in materials in composite wood-concrete beams (wood, concrete, fasteners for composite action); - estimation of slip modulus between wood and concrete for different types of connectors in composite action; - experimental testing of composite wood-concrete beams with different types of connections. _ The goal of the study was the investigation of the behaviour of composite beams under service and ultimate load, with evaluation of stresses and deformations for different phases under the load up to the complete failure. Therefore, eight simple-supported composite beams, with the span of 4.0 m with reinforced concrete slab (b/d = 60/7 cm) and glulam beam (b/h = 10/20 cm) were tested. The composite action was achieved with mechanical fasteners (nails E50/150 and bolts ф10/150), with four different types of a wood-concrete connection. Testing was performed in a separate steel frame, loading was accomplished with a hydraulic press, while deformations were measured with dial-gauges and strain- gauges. Also, experimental evaluation of slip modulus was performed for all types of connections, resulting in a proposal of a model for its experimental determination. Beside the experimental results presented, analytical method for design according to the elastic theory is given, as well as numerical analysis of a composite beam with the use of Finite Element Analysis, together with the comparison of the results. Literature review covers up-to-date theoretical and experimental research studies-as-welbas applications of composite beams in bridges, residential and other structures. Research study results in recommendations for innovation of current standards for wooden and composite structures. In accordance with distinct relevance of the topic and huge potential for the structural application, possible avenues for further research studies for composite wood-concrete beams are given

Clinical significance of extrapulmonary tuberculosis in the differential diagnosis of fever of unknown

Tuberkuloza predstavlja infekciju humanim sojem mikobakterije Mycobacterium tuberculosis uz pojavu karakteristiĉnog imunološkog odgovora organizma. Najĉešća forma bolesti je plućna. Po procenama Svetske Zdravstvene Organizacije (SZO) vanplućna tuberkuloza (VPTB) ĉini oko 20-25% formi bolesti. Zbog uglavnom atipiĉne kliniĉke slike (izuzimajući tuberkulozni meningitis), produţenog toka u kome su uz progresivno pogoršanje opšteg stanja, prisutni još samo povišena temperatura i ĉesto pozitivan zapaljenski sindrom, najveći broj ovih bolesnika se razmatra u toku diferencijalne dijagnoze nejasnog febrilnog stanja (NFS). Poseban problem predstavlja teţa dijagnostika VPTB i potreba za ĉešćim korišćenjem invazivne dijagnostike. U periodu do pojave virusa humane imunodeficijencije (HIV) incidenca tuberkuloze u svetu je bila u opadanju, ali se od osamdesetih godina dvadesetog veka tuberkuloza ponovo nameće kao bolest od rastućeg interesa. Procenjuje se da je u svetu oko dve milijarde ljudi inficiranih bacilom M. tuberculosis od kojih je oko 8 miliona godišnje razvije aktivnu tuberkulozu, a oko 2 miliona umre. Incidenca oboljevanja od tuberkuloze i VPTB je u porastu svugde u svetu i u HIV negativnoj populaciji. U takvim okolnostima raste i znaĉaj informisanosti lekara dijagnostiĉara, da se u toku dijagnostiĉkog postupka febrilnog stanja mora razmatrati i tuberkulozna infekcija, kako pluća, tako i vanplućna. Tuberkuloza moţe zahvatiti bilo koji organ u organizmu, s’tim da je plućna lokalizacija najĉešća. Terminom VPTB se oznaĉava izolovana pojava tuberkuloze na bilo kom mestu u organizmu van pluća. Ako je uz vanplućnu lokalizaciju prisutna i zahvaćenost pluća takvi se pacijenti kategorizuju pod dijagnozom plućne tuberkuloze. Varijeteti kliniĉke slike VPTB su mnogobrojni što oteţava dijagnostiku. Uz retke lokalizacije koje daju karakteristiĉne simptome i znake (meningitis) ili bar mogu uputiti u pravcu dijagnoze (tuberkulozni limfadenitis), većina drugih, posebno dubokih lokalizacija se manifestuje samo povišenom temperaturom. Zbog ovakvih teškoća u dijagnostici, proporcionalno je veća zastupljenost VPTB u ukupnom broju otkrivenih bolesnika sa tuberkulozom u tercijarnim ustanovama, nego u primarnoj zdravstvenoj zaštiti...Tuberculosis is an infection with human mycobacteria strain of Mycobacterium tuberculosis, with the occurrence of the characteristic immune response of the organism. The most common form is lung disease. According to estimates by the World Health Organization (WHO), extrapulmonary tuberculosis (EPTB) accounts for 20-25% of the tuberculosis. Mainly due to atypical clinical features (except for tuberculous meningitis), the prolong course of the illness with progressive deterioration of general condition, present only with fever and often positive inflammatory syndrome, most of theses patients are considered in the differential diagnosis of fever of unknown origin (FUO). A particular problem is a difficult diagnosis of EPTB and the need for more frequent use of invasive diagnostic. Until the appearance of human immunodeficiency virus (HIV) incidence of tuberculosis in the world was in decline, but since the eighties of the twentieth century, tuberculosis re-imposed as a disease of growing interest. It is estimated that the world's two billion people infected with an M. tuberculosis, of which about 8 million develop active TB annually, and about 2 million die. The incidence of tuberculosis and EPTB is increasing everywhere in the world and in the HIV negative population too. In such circumstances, medical doctors must have growing awareness of the importance of tuberculosis infection, both lung and extrapulmonary during the diagnostic procedure in febrile conditions. Tuberculosis can affect any organ in the body; however, the most frequent localization is pulmonary. The term EPTB means an isolated occurrence of tuberculosis anywhere in the body outside the lungs. If present with extrapulmonary localization and involvement of the lungs such patients are categorized under the diagnosis of pulmonary tuberculosis. Varieties of clinical presentations of EPTB are numerous which makes diagnosis difficult. With rare localization which give the characteristic signs and symptoms (meningitis), or at least can make towards the diagnosis (tuberculous lymphadenitis), most of the others, especially the deep localization is only manifested with fever. Because of these difficulties in diagnosis, the greater proportion EPTB was detected in tertiary institutions, instead in primary care. The most common localization of EPTB is tuberculosis of the lymph nodes, genitourinary tuberculosis, abdominal tuberculosis, pleural tuberculosis, tuberculous pericarditis, neurotuberculosis, tuberculosis of bones and joints. Other forms of EPTB occur less frequently..