Screening for Diabetes among Roma People Living in Serbia

Aim To investigate the prevalence of diabetes in the Roma population in Serbia. Methods We screened 11 urban and 8 rural Roma communities from October 2006 to May 2008 for the presence of diabetes. Blood glucose values, name, age, sex, presence of diabetes, family history, and obesity were recorded. Results We analyzed the data from 1465 Roma people, 953 women and 512 men (785 in urban and 680 in rural communities), with mean age of 42.42 ± 15.69 years. Abdominal obesity was present in 600 (41%) participants. Eighty seven participants (5.9%) already had diabetes and there were 76 (5.2%) newly discovered cases of diabetes type 2. Participants with diabetes were significantly older (F = 28.33; P < 0.01). Family history for diabetes was positive in a third of participants. The risk for diabetes was 3.48 times higher in participants with positive family history (odds ratio [OR], 3.47; 95% confidence interval [CI], 2.37-5.1; P < 0.01). Abdominal obesity was less frequent in healthy participants than in participants with diabetes (X2 = 32.55; P < 0.01). The risk of diabetes in participants with abdominal obesity was 2 times higher than in the non-obese (OR, 2.11; 95% CI, 1.24-3.55; P < 0.01). Diabetes was significantly more present in urban communities (X2 = 25.20; P < 0.01). The risk of developing diabetes was 3.65 times higher in participants from urban settlements (OR, 3.64; 95% CI, 1.99- 6.66; P < 0.01). Conclusion Prevalence of diabetes in the Roma people living in Serbia may possibly be higher than in the general population of Serbia and needs further investigation

Numerical study of heat transfer during nucleate pool boiling

U ovom radu je izvršena trodimenzionalna numerička simulacija atmosferskog, zasićenog ključanja u velikoj zapremini. Primenjeni matematički model i numerička metoda omogućavaju potpuni prikaz ponašanja dvofazne mešavine na grejnoj površini kao i predviđanje slobodnog nivoa tečnosti. Ovde prikazano trodimenzionalno istraživanje je sprovedeno kako bi se uzela u obzir konvektivna razmena toplote na grejnoj površini kao i prostorni efekti generacije pare i dvofaznog toka, kao što su disprzija faza u dvofaznoj mešavini. Predstavljeni su rezultati simulacije nakon kratkog vremenskog perioda od početka zagrevanja i formiranja mehurova na grejnoj površini. Prikazani su popunjenost grejne površine vodom i parcijalna okvašenost površine za niže vrednosti toplotnog fluksa. Diskutovan je uticaj gustine nukleacije i vremena zadržavanja mehurova na grejnom zidu na dinamiku ključanja. Takođe je proučen uticaj intenziteta toplotnog fluksa na dinamiku ključanja u velikoj zapremini. Primenjeni numerički metod i matematički model je pokazao ispravnost, omogućavajući stabilan proračun za širok opseg primenjenih parametara pri modeliranju.In this paper three-dimensional numerical simulation of the atmospheric saturated pool boiling was performed. The applied modelling and numerical methods enable full representation of the two-phase mixture behaviour on the heating surface with the inclusion of the swell level prediction. The three-dimensional investigation presented here was performed in order to take into account a convective heat transfer on the heated surface, as well as spatial effects of the vapour generation and a two phase flow such as phase dispersion within the two-phase mixture. The results are presented for a short period of time after the initiation of the heat supply and vapor generation on the heating surface. The replenishment of the heating surface with water and partial surface wetting for lower heat fluxes is shown. The influence of the density of nucleation sites and the bubble residence time on the wall on the pool boiling dynamics is discussed. Also, the influence of the heat flux intensity on the pool boiling dynamics is investigated. The applied numerical and modelling method showed robustness by allowing stable calculations for wide ranges of applied modelling boiling parameters

Screening for Diabetes among Roma People Living in Serbia

Aim To investigate the prevalence of diabetes in the Roma population in Serbia. Methods We screened 11 urban and 8 rural Roma communities from October 2006 to May 2008 for the presence of diabetes. Blood glucose values, name, age, sex, presence of diabetes, family history, and obesity were recorded. Results We analyzed the data from 1465 Roma people, 953 women and 512 men (785 in urban and 680 in rural communities), with mean age of 42.42 ± 15.69 years. Abdominal obesity was present in 600 (41%) participants. Eighty seven participants (5.9%) already had diabetes and there were 76 (5.2%) newly discovered cases of diabetes type 2. Participants with diabetes were significantly older (F = 28.33; P < 0.01). Family history for diabetes was positive in a third of participants. The risk for diabetes was 3.48 times higher in participants with positive family history (odds ratio [OR], 3.47; 95% confidence interval [CI], 2.37-5.1; P < 0.01). Abdominal obesity was less frequent in healthy participants than in participants with diabetes (X2 = 32.55; P < 0.01). The risk of diabetes in participants with abdominal obesity was 2 times higher than in the non-obese (OR, 2.11; 95% CI, 1.24-3.55; P < 0.01). Diabetes was significantly more present in urban communities (X2 = 25.20; P < 0.01). The risk of developing diabetes was 3.65 times higher in participants from urban settlements (OR, 3.64; 95% CI, 1.99- 6.66; P < 0.01). Conclusion Prevalence of diabetes in the Roma people living in Serbia may possibly be higher than in the general population of Serbia and needs further investigation

Antioksidativni učinak fenolnih tvari u ekstraktima pitomog kestena (Castanea sativa Mill.)

Using electron paramagnetic resonance (EPR) spectroscopy, antioxidant properties of chestnut extracts have been investigated as a source of phenolic compounds. In addition to their high antioxidant activities against hydroxyl and organic free (DPPH) radicals, phenolics showed to be potent protectors of membranes from lipid peroxidation. To the best of our knowledge, the ability of an antioxidant to overcome body’s refractory response towards antioxidant supplementation has been examined for the first time. The water soluble extracts obtained from leaves, catkins, and outer brown peel of Castanea sativa Mill. showed high antioxidant activity in scavenging ·OH and DPPH radical. All extracts, except for sweet chestnut catkins, showed the ability to protect liposomes from peroxidation. Phenolic compounds, as active antioxidants, have the ability to enter and protect cell membranes from lipid peroxidation, thus overcoming the body’s refractory response to the antioxidant supplements in the diet. It is shown that phenolics are easily accessible natural antioxidants that can be used as food supplements or for the treatment of pathophysiological conditions related to oxidative stress.Primjenom elektronske paramagnetske rezonantne spektroskopije ispitana su antioksidativna svojstva ekstrakata kestena kao izvora fenolnih spojeva. Osim velikog antioksidativnog učinka na hidroksilne i DPPH radikale, fenolne tvari imaju i sposobnost zaštite staničnih membrana od lipidne peroksidacije. Prema spoznajama autora, po prvi je put ispitana sposobnost antioksidansa da bi se nadvladao tzv. refraktorni odgovor organizma na dijetetske antioksidativne suplemente. U vodi otopljeni ekstrakti lišća, rese i vanjske smeđe kore pitomog kestena (Castanea sativa Mill) imaju veliku sposobnost uklanjanja ·OH i DPPH radikala. Svi ekstrakti, osim ekstrakta resa kestena, sposobni su zaštititi liposome od peroksidacije. Ugradnjom fenolnih spojeva, kao aktivnih antioksidansa, u lipidni dvosloj stanične membrane sprečava se lipidna peroksidacija, čime se može nadvladati tzv. refraktorni odgovor organizma pri dodavanju antioksidativnih suplemenata hrani. Može se zaključiti da su fenolni spojevi lako dostupni prirodni antioksidansi koji bi mogli poslužiti kao dodatak prehrani i sredstvo za ublažavanje posljedica oksidativnog stresa

TECHNO-ECONOMIC OPTIMIZATION OF ENERGY SUPPLY OF A LIVESTOCK FARM

Livestock farming is a significant part of agriculture market in Serbia. A descending trend of livestock species was recorded recently, despite its potential for export of meet. Application of new technologies could improve competitiveness of livestock farming. In this paper, energy efficient energy supply technologies and potentials for their application in livestock farms is analyzed. A methodology for pinpointing profitable energy supply options which also provides significant energy and CO2 savings is proposed. A case study of a pig farm was used to perform an energy balance and allocation of energy supply costs. Potentials for application of energy supply technologies based on local resources were estimated in the study. Effects of integration of proposed technologies were also estimated. The proposed methodology was used to analyze feasibility of proposed energy supply options. Investment in a biogas cogeneration plant showed best profitability. Integrated option which envisages application of heat pump for heat supply and photovoltaic solar collectors for production of electricity showed best energetic and environmental performance, while maintaining financial feasibility

EXPERIMENTAL RESEARCH OF THERMAL PROCESSES IN THE THERMAL STORAGE TANK WITH A PHASE CHANGE MEDIUM

Introduction of thermal storage tanks (TST) in facilities that use renewable energy resources represents a good way to increase their energy efficiency. This paper surveys a part of the activities (performed during the realization of the second year of project III 42011 financed by the Ministry of education and science of the Republic of Serbia) on the development of TST whose storage medium melts at the atmospheric pressure, enabling on that way the use of the energy of phase change for energy storage. TST of this type enable more thermal energy storage per volume unit, but also (depending of the working medium) enable higher temperatures of the working medium, which is necessary in the co-generated facilities. For the purpose of the experimental research of thermal and flow processes in TST in the Laboratory for thermal engineering and energy of the Vinča Institute a prototype of TST was designed and made. It has a cylindrical shape, with the working volume of 77 dm3. The working material is heated by 2.4 kW electric heater positioned along the TST axes, and is cooled by the air which circulates around the tank. The measurement of temperature inside the tank was performed by 16 thermocouples, 4 along the tanks height and 4 along the tanks radius. For the purpose of this work paraffin as a working medium was used. Measurements were performed for non-stationary as well as for stationary working regimes. As a result, an extensive set of experimental data was obtained, which, in the later work on the project, will serve in the numerical study, as a basis for the developing a numerical model, to verify its results and, if necessary, to correct the model

Eksploatacioni pokazatelji TMA za dopunsku obradu zemljišta u višegodišnjim zasadima

Fruit production under arid conditions without irrigation implies the need to employ soil cultivation in the entire orchard with the aim of regulating the water-air regime of the soil, contributing to a favorable soil structure, breaking down the soil crust and successful weeds destruction. Contemporary fruit cultivation practices are compulsory in order to achieve high yields and profitability. Additional soil tillage in orchards has a major impact on the growth and development of plants, yield and fruit quality. Optimal parameters need to be determined when employing mechanization equipment in orchard cultivation in order to make the right choice. The objective of the study was to determine energetic and exploitation parameters of different tractor/machinery tools used in additional soil cultivation. Based on the analysis of the data obtained showing both advantages and disadvantages of some soil cultivation types, it was possible the choose the optimal tool for additional soil tillage. Field trials were carried out in apple (cv. Jonagold, Idared and Melrose) orchards using the two-row Pilar cultural practice at a planting distance 3.80-1.25 x 140-1.80 m. The following tools for additional soil cultivation were used: pseudo plow PP-220, plate cultivator VVT - 223, cultivator IMT-642 and vineyard plow VP-189. The following exploitation indices were monitored: traction force, labor speed, fuel consumption and traction resistance. Based on the results obtained the smallest fuel consumption was registered using pseudo plow (3.78 l/ha) whereby cultivation depth, speed and output registered were 6.31 cm, 7.29 km/ha and 9.07 ha/day respectively.Proizvodnja voća u aridnim uslovima bez navodnjavanja zahteva obradu zemljišta na čitavoj površini u cilju regulisanja vodno-vazdušnih osobina zemljišta, stvaranja pogodne strukture, razbijanja pokorice i uništavanja korovske vegetacije. Primena takve tehnologije gajenja voća je neophodna za ostvarenje visokih prinosa i ekonomične proizvodnje. Zbog toga dopunska obrada zemljišta u višegodišnjim zasadima ima značajan uticaj na rast i razviće biljaka, prinos i kvalitet plodova. Pravilan izbor i korišćenje sredstava mehanizacije ima presudan uticaj na intenzivnost voćarske proizvodnje. Napredak u tehnologiji gajenja voća podrazumeva korišćenje najsavremenijih tehničkih sredstava za obavljanje agrotehničkih mera. Za pravilan izbor pojedinih sredstava mehanizacije značajno je utvrditi optimalne parametre njihove primene u obradi zemljišta. Utvrđivanje energetskih i eksploatacionih parametara rada različitih traktorsko-mašinskih agregata pri dopunskoj obradi predstavlja predmet ovog istraživanja. Analiza dobijenih podataka, koji ukazuju na prednosti i nedostatke pojedinih načina obrade omogućuje izbor optimalnog agregata za dopunsku obradu u zasadima. Rezultati ispitivanja sredstava mahanizacije u dopunskoj obradi međuredne površine, pokazuju da je najmanja potrošnja goriva ostvarena kod čizel pluga (3,78 l/ha). Njegovim korišćenjem postignuta je dubina rada 6,31 cm, brzina 7,29 km/h i ostvaren učinak od 9,07 ha/dan

DYNAMIC BEHAVIOUR OF HOT WATER BOILERS DURING START UP

The most commonly used central units in the district heating system are most certainly hot water boilers. Experience in exploitation as well as their former development have given rise to new demands and possibilities of using hot water boilers for achieving a more efficient utilization of fuel. Yet, the current trend is not only for an efficient operation in terms of energy efficiency of primary fuel, but it also comprises many strict requirements when it comes to a cost-effective, reliable and safe operation. A mathematical - empirical model of the hot water boiler during the start-up process is presented in this paper. The dynamic behavior of the object will be discussed in the start-up regime because it represents one of the most critical transient regimes during the operation

TECHNO-ECONOMIC OPTIMIZATION OF ENERGY SUPPLY OF A LIVESTOCK FARM

Livestock farming is a significant part of agriculture market in Serbia. A descending trend of livestock species was recorded recently, despite its potential for export of meet. Application of new technologies could improve competitiveness of livestock farming. In this paper, energy efficient energy supply technologies and potentials for their application in livestock farms is analyzed. A methodology for pinpointing profitable energy supply options which also provides significant energy and CO2 savings is proposed. A case study of a pig farm was used to perform an energy balance and allocation of energy supply costs. Potentials for application of energy supply technologies based on local resources were estimated in the study. Effects of integration of proposed technologies were also estimated. The proposed methodology was used to analyze feasibility of proposed energy supply options. Investment in a biogas cogeneration plant showed best profitability. Integrated option which envisages application of heat pump for heat supply and photovoltaic solar collectors for production of electricity showed best energetic and environmental performance, while maintaining financial feasibility

Advantages of use thermal storage tank when using biomass as energy source

Biomasa je najveći potencijal obnovljive energije u Republici Srbiji. Postoji zaostatak u njenoj organizovanoj, specijalno industrijskoj, upotrebi u odnosu na potencijal. Pored niza objektivnih okolnosti zašto je to tako jedan leži i u karakteristikama rada kotlova i ložišta u kojima se primenjuje biomasa. Kotlovi i ložišta u kojima se primenjuje biomasa moraju dobrim delom biti ozidani (adijabatski) kako bi se stvorili uslovi potpunog sagorevanja i na niskim temperaturama. Niske temperature sagorevanja su poželjne zbog niske temperature topivosti pepela. To specijalno važi pri primeni poljoprivredne biomase. Takve kotlove i ložišta nije poželjno često paliti i gasiti, već je povoljno da oni rade u kontinuitetu. Pored toga takvi kotlovi i ložišta nemaju mogući raspon snaga kao slični uređaji koji rade na gasovito ili tečno gorivo. Obično mogu raditi u opsegu snaga 50-100%. Sa druge strane očekuje se da se takvi kotlovi najviše koriste u sistemima za grejanje i/ili u industrijskim pogonima za preradu poljoprivrednih proizvoda ili za njihov uzgoj. Ni jedna od navedenih očekivanih primena nema potrebu za kontinualnim radom niti ujednačenu potrebu za energijom tokom rada. U radu je prikazano, kroz primere u praksi, kako se navedeni problemi mogu rešiti ili ublažiti primenom akumulatora toplote, a bez povećanja ili sa minimalnim povećanjem investicionih troškova.Biomass represents the largest renewable energy sources in the Republic of Serbia. Still, there exists a huge gap between this potential and its organized use, especially in industry. One of the reasons for this lies in characteristics of boilers and furnaces that use biomass. In order to fulfill conditions for complete biomass combustion even at low temperatures these furnaces have to be adiabatic. Low combustion temperatures are desirable due to the low melting temperatures of biomass ash (especially in case of agricultural biomass). Such boilers and furnaces should work continually. Their usual power range is 50-100%. On the other side, they are expected to be used most often for heating or in industrial plants that produce agricultural products. Their common characteristic is that they do not have need for continual energy supply during work. This paper show, through few examples, how such problems could be solved in practice using thermal energy storages, without or with minimal additional costs