Review of membrane contactors designs and applications of different modules in industry

Nov način primene membranskih procesa u prečišćavanju voda iz različitih industrija je korišćenje membranskih kontaktora. Tehnologija membranskih kontaktora ima primene u tretmanu otpadnih voda, farmaceutskoj industriji fermentaciji, proizvodnji poluprovodnika, ekstrakciji proteina, karbonizaciji pića, uklanjanju isparljivih organskih komponenata (VOC) iz otpadnog gasa i tako dalje. Membranski sistemi projektovani da formiraju kontakt između dve komponente (tečno / tečno, tečno/gas i gas/gas) su zajednički definisani kao membranski kontaktori. Membranski kontaktori su uređaji koji postižu prenos materije u sistemu gas/tečnost ili tečnost/tečnost bez disperzije jedne faze unutar druge. Membrana se koristi za separaciju i transport radne komponente mnogo lakše u odnosu na druge usled razlika u fizičkim i/ili hemijskim karakteristikama između membrane i komponenata. Postoji nekoliko prednosti pri korišćenju membranskih kontaktora u odnosu na konvencionalne metode. Neke od njih su: ne postoji plavljenje pri visokim protocima, zadržavanje radnih karakteristika pri niskim protocima, odsustvo emulzije, nema razlike gustina traženih fluida i velika površina. Glavni cilj ovog rada je bio pregled karakteristika i primene membranskih kontaktora, posebno primene kontaktora za izdvajanje rastvorenog kiseonika iz vodenih rastvora uz pomoć vakuuma.New way for applying membrane processes for purification water in different industries is using membrane contactors. Membrane contactor technology has applications in wastewater treatment, pharmaceuticals, fermentation semiconductor manufacturing, protein extraction, carbonation of beverages VOC removal from waste gas and so forth. Membrane systems that are designed to form an interface between two components (liquid/liquid, liquid/gas, and gas/gas) are commonly referred to as membrane contactors. The membrane contactors are devices that achieve gas/liquid or liquid/liquid mass transfer without dispersion of one phase within the other. The membrane is used to accomplish a particular separation and transport of one component more easily than another because of differences in physical and/or chemical properties between the membrane and the permeating components. There are a few advantages to using membrane contactors in contrast to conventional methods. Some of them are no flooding at high flow rates, no unloading at low flow rates, absence of emulsions, no density difference between fluids required, and high interfacial area. The main goal in this paper has been a general review of membrane contactor designs and operations, especially in applying of contactors for removing dissolved oxygen from aqueous solutions by vacuum degassing

Review of membrane contactors designs and applications of different modules in industry

Nov način primene membranskih procesa u prečišćavanju voda iz različitih industrija je korišćenje membranskih kontaktora. Tehnologija membranskih kontaktora ima primene u tretmanu otpadnih voda, farmaceutskoj industriji fermentaciji, proizvodnji poluprovodnika, ekstrakciji proteina, karbonizaciji pića, uklanjanju isparljivih organskih komponenata (VOC) iz otpadnog gasa i tako dalje. Membranski sistemi projektovani da formiraju kontakt između dve komponente (tečno / tečno, tečno/gas i gas/gas) su zajednički definisani kao membranski kontaktori. Membranski kontaktori su uređaji koji postižu prenos materije u sistemu gas/tečnost ili tečnost/tečnost bez disperzije jedne faze unutar druge. Membrana se koristi za separaciju i transport radne komponente mnogo lakše u odnosu na druge usled razlika u fizičkim i/ili hemijskim karakteristikama između membrane i komponenata. Postoji nekoliko prednosti pri korišćenju membranskih kontaktora u odnosu na konvencionalne metode. Neke od njih su: ne postoji plavljenje pri visokim protocima, zadržavanje radnih karakteristika pri niskim protocima, odsustvo emulzije, nema razlike gustina traženih fluida i velika površina. Glavni cilj ovog rada je bio pregled karakteristika i primene membranskih kontaktora, posebno primene kontaktora za izdvajanje rastvorenog kiseonika iz vodenih rastvora uz pomoć vakuuma.New way for applying membrane processes for purification water in different industries is using membrane contactors. Membrane contactor technology has applications in wastewater treatment, pharmaceuticals, fermentation semiconductor manufacturing, protein extraction, carbonation of beverages VOC removal from waste gas and so forth. Membrane systems that are designed to form an interface between two components (liquid/liquid, liquid/gas, and gas/gas) are commonly referred to as membrane contactors. The membrane contactors are devices that achieve gas/liquid or liquid/liquid mass transfer without dispersion of one phase within the other. The membrane is used to accomplish a particular separation and transport of one component more easily than another because of differences in physical and/or chemical properties between the membrane and the permeating components. There are a few advantages to using membrane contactors in contrast to conventional methods. Some of them are no flooding at high flow rates, no unloading at low flow rates, absence of emulsions, no density difference between fluids required, and high interfacial area. The main goal in this paper has been a general review of membrane contactor designs and operations, especially in applying of contactors for removing dissolved oxygen from aqueous solutions by vacuum degassing

Improvement possibilities of the I-V characteristics of PIN photodiodes damaged by gamma irradiation

This paper presents the behavior of PIN photodiodes after combined gamma and neutron irradiation. Different types of PIN photodiodes have been exposed first to gamma and then to neutron irradiation. I-V characteristics (current dependence on voltage) of photodiodes have been measured after each of these irradiations. It has been noted that the photocurrent level after the neutron irradiation is higher than before it, which is not consistent with the current theories about the effects of neutron radiation on semiconductors. In order to explain this behavior of the photodiodes, the Monte Carlo simulation of photon transport through the material has been used. It is proposed that a possible cause for current enhancement are defects in semiconductor created by gamma irradiation and effects of neutron irradiation on these defects. The results can be explained by an intercentre transfer of charge between defects in close proximity to each other. The aim of this paper is to investigate the improvement possibilities of the I-V characteristics of PIN photodiodes, and photodetectors in general, damaged by gamma irradiation. [Projekat Ministarstva nauke Republike Srbije, br. 171007

Rendgenološka procena apeksogeneze nakon primene hidroksiapatita

The treatment of pulp in teeth with incomplete apex formation is still a clinical challenge. In addition to the most widely used medication for this purpose, calcium hydroxide, other materials have also been tested. Following the use of synthetic biomaterials for restoring bone tissue, and considering their recognized biocompatibility and bioconductivity, our intention was to explore the possibility of using synthetic biomaterials in the endodontic treatment of permanent teeth with incomplete apex formation. The aim of this study was to observe the effectiveness of hydroxyapatite in apexogenesis of young permanent teeth. In this study a 100 µm synthetic hydroxyapatite material, Beohap (HAP) powder, was applied to 24 teeth in 3 dogs of 5.5 months of age, after incomplete root development was established on radiographs. The treated teeth were radiographed monthly and the radiographs compared with those of the corresponding teeth on the other side of the jaw until completion of apex growth. The tested teeth were divided into three groups according to the method of treatment: the first was direct pulp capping, the second was amputation of the pulp at the enamelcement junction and the third was high amputation at the radiographically identified point of root growth. On the basis of radiographic analysis, apex formation was successful in all test groups, with no significant differences between the three groups and the controls (Fisher's and χ 2 test). Deformities of the root apex were observed in two teeth (25%) in the third group.Tretman pulpe u vreme kada još uvek traje rast i razvoj korena predstavlja i dalje klinički izazov. Pored kalcijum hidroksida, najčešće i najduže upotrebljavanog medikamenta u ovakvim slučajevima, svakodnevno se testiraju i mnogi drugi materijali. Nakon što su se sintetski biomaterijali pokazali uspešnim u restauraciji koštnog tkiva uz njihovu priznatu biokompatibilnost i biokonduktivnost, naša namera je bila da istražimo mogućnost primene hidroksiapatita kao sintetskog biomaterijala u endodontskom tretmanu zuba sa nezavršenim rastom korena. U ovom istraživanju primenjen je Beohap, sintetski hidroksiapatit, prosečne veličine čestica =100 µm, aplikovan na 24 zuba sa nezavršenim rastom korena kod tri psa uzrasta 5,5 meseci. Uzrorci su kontrolisani radiografski i poređeni sa kontralateralnim netretiranim zubima do završetka rasta korena. Tretirani zubi su podeljeni u tri grupe: u prvoj je urađeno direktno prekrivanje pulpe, u drugoj je pulpa uklonjena do cementno-gleđne granice, a u trećoj je pulpa uklonjena do radiografski vidljivog vrha korena. Na osnovu analize rendgen filmova utvrđeno je da je formiranje vrha korena bilo završeno u sve tri grupe bez statističkih značajnosti razlika (Fisher's i χ 2 testovi) Deformiteti vrha korena uočeni su u 2 uzorka u trećoj grupi (25%)

Uticaj poslovnog okruženja na performanse sektora MSPP u Srbiji

Predmet rada je analiza kvaliteta poslovnog okruženja u Republici Srbiji i sagledavanje njegovog uticaja na poslovne performanse malih i srednjih preduzeća (MSP) i preduzetnika (MSPP). Cilj rada je da se identifikuju kritični faktori iz eksternog okruženja koji imaju presudan uticaj na poslovanje MSPP, kao i da se istraži kako oni utiču na razvoj ovog sektora srpske privrede. Pored toga, u radu je učinjen pokušaj sagledavanja određenih faktora interne prirode (jakih i slabih strana) sa kojima se suočavaju pomenuti privredni subjekti u našoj zemlji. Uzimajući u obzir dejstvo identifikovanih egzogenih i endogenih faktora na poslovanje preduzeća, autori rada predlažu određena rešenja za unapređenje poslovanja MSPP. Ključni elementi modela se zasnivaju na adekvatnom i pravilnom dijagnostikovanju problema, uvažavanju elemenata strategijskog razmišljanja i kvalitetnoj implementaciji definisanih strategijskih odluka

Neutrophil phagocytosis and respiratory burst activity of dairy cows during the transition period and early lactation

Introduction: Hormonal and metabolic changes, as well as energy imbalance, can affect health, production and reproductive performance of dairy cows. In the present study, we evaluated phagocytosis and respiratory burst neutrophil activity during the transition period and early lactation and compared it with biochemical and hematological parameters in dairy cows. Methodology: Simmental cows (n = 21) were enrolled in the study. Whole blood samples were collected weekly from 3 weeks pre- calving until 6 weeks post calving. Basic metabolic and blood parameters were assessed by routine laboratory analyses, while neutrophil functions were analyzed by commercial test kits. Results: Optimal neutrophil response was observed pre and post calving. The highest value was recorded in the 6th week after calving (89.54 +/- 7.61%) and being significantly higher (p < 0.01) as compared to values recorded at two and one week before and one week after calving. The percentage of activated neutrophils was high during the entire study period: from 70.80 +/- 5.22% at the beginning of the study to 89.54 +/- 7.61% at the end of the study. During the study period, production of Reactive Oxidative Species by neutrophils was positively correlated with beta-hydroxybutyrat and non-esteri tied fatty acids values (0.454** and 0.423**, respectively) and calcium levels (0.164* and 0.212**, respectively). Conclusions: The most prominent changes in all parameters had no influence on phagocytic and respiratory burst activity of neutrophils. Neutrophil function is preserved at the optimal level during the transition period and early lactation in Simmental cows

Toxicological analysis of the risk of lead exposure in metal processing

Purpose: To evaluate toxicological risks for workers who are exposed to lead in their work environment. Methods: Since it is an important indicator of toxicological risk, a statistical analysis of lead concentration and biological lead toxicity markers in blood and urine were performed for both exposed and control groups. Both experimental groups consisted of employees from "NISSAL" JSC factory. Analytical epidemiological method in the form of a retrospective cohort study was applied, and covered the period from 2001 to 2010. The concentration of lead, δ-aminolevulinic acid, and coproporphyrin in biological samples were determined by spectrophotometric methods. Results: The results showed a high positive correlation between lead concentrations in blood and urine and the length of exposure of the participants (p &lt; 0.01). Also, increase of lead concentration in the biological material significantly increased δ-aminolevulinic acid (p &lt; 0.01) and slightly increased the concentration of coproporphyrin, both of which are important indicators of toxicological risk. Conclusion: The control group of employees belonged to the normal risk category, while the exposed group belonged to a moderate risk category. Correlation between the monitored parameters is statistically significant at p &lt; 0.01 and p &lt; 0.05. Keywords: Lead, δ-Aminolevulinic acid, Coproporphyrin, Chronic exposure, Toxicity, Correlatio

Ispitivanje prisustva antitela protiv goveđeg herpesvirusa-1 u krvnom serumu teladi pre ishrane kolostrumom

The paper presents the results of investigations of the presence of the bovine herpesvirus-1 (BHV-1) in samples of blood serum from 106 cows and 107 of their calves (one cow had twins). Blood was sampled from the cows immediately after parturition, and from the calves before feeding on colostrum. The examined cows and their calves originated from 5 herds in which previous investigations had shown infection with the bovine herpesvirus-1. The determination of antibodies against BHV-1 was performed using the method of virus neutralization in culture of MDBK cells with 100 TCID/50 viruses (BHV-1, TN-41 Am. Bio Research, USA). Antibodies against BHV-1 were determined in all blood serum samples of cows and in 16 samples of precolostral blood serums of calves. The antibody titer values in cows ranged from 1:4 to 1:512, and in calves the determined values were from 1:2 to 1:16. The results indicate that cows that are seropositive to BHV-1 can deliver calves seropositive to BHV-1 in about 15% cases. This must be kept in mind in selecting cows for the production of breeding material, in particular bulls for reproduction centers, as well as in making a programme for the immunoprophylaxis of calves against BHV-1. .U radu su prikazani rezultati ispitivanja prisustva antitela protiv goveđeg herpesvirusa-1 (BHV-1) u uzorcima krvnih seruma 106 krava i 107 njihove teladi (jedna krava je otelila blizance). Uzorkovanje krvi od krava je vršeno odmah nakon partusa, a od teladi pre ishrane kolostrumom. Ispitivane krave i njihova telad poticali su iz 5 zapata u kojima je ranijim ispitivanjima utvrđena infekcija goveđim herpesvirusom-1. Utvrđivanje antitela protiv BHV-1 vršeno je metodom virus neutralizacije na kulturi MDBK ćelija sa 100 TCID/50 virusa (BHV-1, TN-41 Am. Bio Research, USA). Antitela protiv BHV-1 utvrđena su u svim uzorcima krvnih seruma krava i u 16 uzoraka prekolostralnih krvnih seruma teladi. Vrednosti titra antitela iznosile su kod krava od 1:4 do 1:512, a kod teladi od 1:2 do 1:16. Rezultati ukazuju na to da krave koje su seropozitivne na BHV-1 mogu da otele telad seropozitivnu na BHV-1 u oko 15% slučajeva. Ovo se mora imati u vidu kada se vrši izbor krava za proizvodnju priplodnog materijala, a posebno bikova za reprocentre, kao i kada se pravi program imunoprofilakse teladi protiv BHV-1.

EPIDEMIOLOGICAL CHARACTERISTICS OF Q FEVER IN THE SREM DISTRICT OF VOJVODINA, FROM 2011 TO 2020

Q fever is a globally widespread zoonosis, which has a large number of animal reservoirs. In humans, Q fever is asymptomatic in 60% of cases but may appear in the form of acute or chronic disease. The disease is mostly asymptomatic in animals but may be a cause of abortions or stillbirths. The aim of this study was to present and analyze the epidemiological characteristics of Q fever in Srem district, in the Autonomous Province of Vojvodina, Republic of Serbia. We conducted a descriptive study using data from the registries of infectious diseases of the Institutes of Public Health of Vojvodina and Institute of Public Health Sremska Mitrovica in the period 2011-2020. A total of 76 human cases of Q fever were registered in Srem district over ten-year period. The majority of patients (89.47%; N = 68) were registered in municipalities of Sremska Mitrovica and Šid. One third of patients were hospitalized (32.89%; N = 25). Males were 3.2 times more affected than females (M : F = 3.22 : 1). Working age population (20–59 years) were most affected (82.89%; N = 63) with a significantly higher incidence compared to the age category 0-19 years (p < 0.05). The majority of cases were registered in February (60.53%; N = 46). Probable routes of transmission of Coxiella burnetii were: direct contact with animals and the airborne route of transmission (50.00% vs. 47.37%). The highest seroprevalence of Q fever recorded in goats (55.54%) and sheep (11.88%) in the municipality of Šid, which is connected to outbreak in Kukujevci 2017. The high seroprevalence in goats, recorded in Inđija (22.87%) was not accompanied by Q fever in humans. Q fever still represents a significant problem of both veterinary and human medicine and therefore continuous disease monitoring and more efficient cooperation of the veterinary and human health care sectors is necessary