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Phase diagram evaluation and experimental characterization of the Al-Bi-Ge ternary system
No full textIn this work, the ternary system Al-Bi-Ge has been studied. Phase diagrams were calculated using Pandat software while experimentally tested alloys come from three vertical and two isothermal sections. The three vertical sections Al-BiGe, Bi-AlGe and Ge-AlBi were investigated by differential thermal analysis (DTA) and experimental phase diagrams were compared with calculated ones based on the experimental results. Selected alloys from the isothermal section at 400 °C and as-cast samples were investigated by X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). The microstructure of the investigated samples was characterized by optical microscopy (OM) and the scanning electron microscopy (SEM). The microstructure of all samples annealed at 400 °C, consists of three phases L, (Al) and (Ge), while in the microstructure of as-cast samples phases (Al), (Bi) and (Ge) are detected. Microstructure of as-cast samples were compared with calculated isothermal section at 25 °C. Brinell hardness, electrical conductivity and electrical resistivity were measured for selected ternary alloys. Based on the experimental values and using a suitable mathematical model, these properties were predicted by RSM methodology for all composition ranges
Seasonal trends in water quality and their implications for water treatment technology in drinking water production
No full textGlavni fokus u cilju zaštite vode je plansko i naučno zasnovano iskorišćavanje vodnih resursa, kao i primena i optimizacija tehnoloških postupaka za pripremu pitke vode. Proizvodni pogon „Makiš“, preradom sirove savske vode Degremon (franc. Degremont) tehnologijom, zadovoljava skoro 60% potreba grada Beograda za pitkom vodom. Upotreba koagulanta, flokulanta i hlora je neophodna kako bi kvalitet vode bio u skladu sa Pravilnikom o higijenskoj ispravnosti vode za piće (Službeni glasnik RS, br. 28/2019). Cilj istraživanja bio je da se analiziraju sezonski trendovi u kvalitetu sirove vode reke Save i njihove implikacije na tehnologiju prerade površinske vode, kroz ispitivanje korelacije između fizičko-hemijskih parametara sirove vode i utroška hemikalija (koagulant, flokulant i hlor). Korišćenjem Pirsonove korelacione matrice, utvrđena je međusobna povezanost kvaliteta sirove vode i količine primenjenih hemikalija, što omogućava optimizaciju tehnološkog procesa prerade i efikasnije upravljanje resursima.The primary objective of water protection is the planned and scientifically based management of water resources, along with the implementation and optimization of technological processes for drinking water treatment. The "Makiš" water treatment plant, utilizing Degremont technology, meets nearly 60% of Belgrade's drinking water requirements by processing raw water sourced from the Sava River. The application of coagulants, flocculants, and chlorine is critical to ensuring that water quality adheres to the standards outlined in the Book of Rules regarding the hygienic safety of drinking water (Official Gazette of the RS No. 28/2019). This study aims to analyze seasonal variations in the quality of raw water from the Sava River and their implications for surface water treatment technology by investigating the correlation between the physicochemical parameters of raw water and the consumption of treatment chemicals (coagulants, flocculants, and chlorine). By employing Pearson's correlation matrix, we can ascertain the relationship between raw water quality and the amount of chemicals used, facilitating the optimization of the treatment process and enhancing resource management efficiency
Fracturing in 14MoV6-3 Steel Weld Joints—Including Base Metals—After a Short Time in Service
No full textIn order to establish the influence of prolonged exposure to high temperatures on 14MoV6-3 steel, three different weld joints were designed. New-to-new material, new-to-used material, and used-to-used material joints were welded using two welding technologies—GTAW and a combination of GTAW + MMA. The weldments were tested by means of microstructure and tensile testing. The results showed that in all weldments, a fracture occurred in the base metal. Also, in the case of the new-to-used welded sample, the fracture always occurred in the used base metal. Since both materials have the same chemical composition, the difference in microstructure was related to long exposure to high temperatures. New steel has a considerably smaller grain size, while the used material underwent grain growth coupled with carbide coarsening, which decreased its strength. The yield strength (YS) of the new material was higher than the YS of the used material, which exhibited similar values in the used base metal and both weldments. It can be assumed that, since deformation starts in the area with the lowest yield point, the used material is the critical place in a given weldment. Therefore, the accurate extent of strength decrease cannot be evaluated based on the testing of new material, i.e., there is a need to reconsider the traditional qualifications of welding technology
Acesulfame in the Water of Belgrade’s Ranney Wells as a Marker of Municipal Pollution
No full textU nedostatku postrojenja za prečiščavanje komunalnih otpadnih voda na teritoriji Beograda,
velika količina netretirane kanalizacione vode, koja sa sobom nosi različite zagađujuće materije i
patogene organizme, se kontinuirano ispušta u reke Savu i Dunav. Posebnu zabrinutost izaziva mogućnost
transporta zagađujućih materija kroz slojeve akvifera do podzemnih voda i Reni-bunara
izgrađenih duž toka reke Save, koji predstavljaju glavni izvor snabdevanja vodom za piće u Beogradu.
Hemijski markeri zagađenja poput veštačkih zaslađivača mogu biti dobar alat u proceni infiltracije
kanalizacionog zagađenja, zbog njihove velike postojanosti u životnoj sredini i specifičnosti za komunalne
otpadne vode. U ovom radu, u cilju procene uticaja kanalizacionog zagađenja na vodoizvorište,
ispitivano je prisustvo veoma perzistentnog veštačkog zaslađivača acesulfama u uzorcima podzemne
vode iz sedam beogradskih Reni bunara na obali reke Save u Beogradu. Analiza uzoraka vode
je izvršena pomoću tečne hromatografije u sprezi sa tandem masenom spektrometrijom. Rezultati su
pokazali prisustvo acesulfama u četiri od sedam Reni bunara u opsegu koncentracija od 77,7 ng L–
1 do 262,1 ng L–1. Na različite nivoe detektovanih koncentracija ovog jedinjenja uticali su heterogenost
akvifera reke Save, udaljenost od toka, kao i prisustvo nelegalnih objekata sa dodatnim komunalnim
opterećenjem u neposrednoj blizini pojedinih Reni bunara. S obzirom da je zaštićenost
beogradskog vodoizvorišta od presudne važnosti za vodosnabdevanje i proizvodnju vode za piće zadovoljavajuće
zdravstvene i higijenske ispravnosti, prisustvo acesulfama u Reni bunarima ukazuje na
neophodnost uvođenja postrojenja za prečišćavanje komunalnih otpadnih voda u Beogradu, kao i
zabranu izgradnje objekata u užoj zoni sanitarne zaštite.In the absence of municipal wastewater treatment plants in Belgrade, a large amount of untreated
sewage, containing various pollutants and pathogenic organisms, is continuously discharged
into the Sava and Danube rivers. Of particular concern is the potential for these pollutants to be
transported through the aquifer layers to the groundwater and Ranney wells built along the course
of the Sava River, which represent the main source of drinking water supply in Belgrade. Chemical markers of pollution, such as artificial sweeteners, can be good tools for evaluating the infiltration
of sewage pollution due to their high persistence in the environment and specificity for municipal
wastewater. In this paper, in order to assess the impact of sewage pollution on the water source, the
presence of the highly persistent artificial sweetener acesulfame was investigated in groundwater
samples from seven Belgrade Ranney wells on the banks of the Sava River. Analysis of water samples
was performed using liquid chromatography – tandem mass spectrometry. The results showed the
presence of acesulfame in four of the seven Ranney wells in the concentration range from 77.7 ng L–
1 to 262.1 ng L–1. The different levels of detected concentrations of this compound were influenced
by the heterogeneity of the aquifer of the Sava River, the distance from the river course, as well as
the presence of illegal facilities with an additional wastewater burden in the immediate vicinity of the
certain Ranney well. Given that the protection of the Belgrade's water source is of crucial importance
for water supply and production of drinking water of satisfactory health and hygiene standards, the
presence of acesulfame in Ranney wells indicates the necessity of introducing facilities for the treatment
of municipal wastewater in Belgrade, as well as the prohibition of the construction of facilities
in the narrow zone of sanitary protection
Probiotic as wound dressing: Probiotic immobilization and release from AC pads
No full textIntroduction: One of the key challenges in developing efficient probiotic
systems for various applications, such as wound dressing, is ensuring
effective cell preservation. Immobilization is a well-established technique
widely used across various industries. A fundamental requirement of any
immobilization technology is maintaining the viability of bacterial cells,
which plays a key role in selecting the appropriate method. The freezedrying is widely regarded as the gold standard in the biopharmaceutical
industry. However, the freezing phase can cause cellular damage due to ice
crystal formation and osmotic stress. To minimize such damage, various
protectants are often added to the drying medium. Another crucial factor is
the controlled release of cells into the surrounding environment. Depending
on the application, it may be necessary to release a large number of cells
rapidly, or in some cases, a sustained and gradual release is more desirable.
Here, we selected 100% activated carbon fabric (AC pads), which is usually
used in medicine to neutralize odors, as support for probiotic immobilization..
Impact of glucose and oxygen on osteochondral-synovium co-culture
No full textIntroduction
There are several challenges in using ex vivo and in vitro culture models in cartilage research.
Monocultures fail to replicate the complex interactions between cartilage, synovium, and
subchondral bone. Additionally, glucose and oxygen levels vary significantly across studies,
with no standardized protocols. This study aims to develop an ex vivo co-culture system with
osteochondral and synovium tissues and investigate the impact of glucose levels in the
establishment of an ex vivo joint model under different oxygen conditions. ..
Aktivni ugalj kao nosač probiotika:novi pristup eliminaciji patogena u ranama
No full textOtpornost na antibiotike je jedna od najvećih pretnji javnom zdravlju, bezbednosti hrane i globalnom razvoju i zato je neophodno više istraživanja u cilju identifikacije, razvoja, primeni i proceni novih inovativnih terapija. Dvogodišnji projekat ProHealingAC koji je podržan od strane Fonda za nauku Republike Srbije, ima za cilj da iskoristi blagotvorna svojstva aktivnog uglja i probiotskih mikroorganizama u cilju razvoja nove strategije za prevenciju i lokalno lečenje rezistentnih patogena u ranama. Cilj ovog projekta je razvoj biokompozita (BK) na bazi tkanine od aktivnog uglja, kao adsorpcione komponente, i probiotika, kao bioaktivne komponente, kako bi se postigla njihova sinergijska aktivnost u cilju efikasne lokalne isporuke bioaktivnih agenasa direktno u područje rane. Takođe, posebna pažnja je posvećena uticaju nivoa glukoze (normo- i hiperglikemije) u mikrookruženju rane. Multidisciplinarni tim će razviti efikasne, jednostavne i isplative BK kombinovanjem principa inženjerstva i biomedicine (mikrobiologije, molekularne biologije i medicine). Razvijeni BK će biti sveobuhvatno okarakterisani u in vitro uslovima u pogledu profila oslobađanja probiotika, antimikrobne i antibiofilm aktivnosti i modulacije aktivnosti makrofaga, fibroblasta i keratinocita. Na osnovu dobijenih rezultata biće izabran najbolji kandidat za in vivo studije na modelu rane kod dijabetičkih i nedijabetičkih životinja. Kao primarni rezultat, konstituisan je konzorcijum od pet naučnoistraživačkih organizacija i izrađen je detaljan plan istraživanja. Stručnost u oblasti biotehnologije, mikrobiologije, molekularne biologije i histopatologije partnera uključenih u projekat činiće solidnu osnovu za uspešno izvršenja planiranih aktivnosti. Glavni cilj projekta ProHealingAC je razvoj novih nekonvencionalnih antiinfektivnih BK sa produženim oslobađanjem probiotika za prevenciju i lokalni tretman rezistentnih infekcija sa posebnim osvrtom na uticaj nivoa glukoze u mikrookruženju rane. Pored toga, kroz efikasnu diseminaciju i komunikaciju rezultata, projekat ProHealingAC će pomoći podizanju svesti ljudi o značaju racionalne upotrebe antibiotika
Antypirine triarylmethine dye synthesis and its application in textile dyeing
No full textDi- i triarilmetinske boje (ranije poznate kao di- i triarilmetanske boje) se odlikuju prisustvom sp2-hibridizovanog centralnog atoma ugljenika, što rezultuje planarnom geometrijom molekula. Planarnost, u kombinaciji sa π-konjugacijom, omogućava apsorpciju svetlosti u vidljivom delu spektra, što molekulu daje karakterističnu boju. Ove boje se procesom adsorpcije mogu uspešno vezati za podlogu (tekstilni materijal). U ovom radu triarilmetinska boja je pripremljena oksidacijom odgovarajućeg triarilmetana. Triarilmetan je pripremljen polazeći od 4-dimetilaminobenzaldehida i antipirina primenom nekoliko postupaka: sinteza bez rastvarača korišćenjem cink-hlorida, sinteza bez rastvarača korišćenjem p-toluensulfonske kiseline i sinteza korišćenjem hlorovodonične kiseline. Dobijeni triarilmetan je zatim oksidovan korišćenjem gvožđe(III)-hlorida u cilju dobijanja triarilmetinske boje. Dobijeni molekuli su okarakterisani temperaturom topljenja, 1H NMR, FT-IR i masenom spektroskopijom. Pored toga, UV-Vis analiza boje je urađena u organskim rastvaračima, kao i u vodenim rastvorima različitog pH. Analizom je potvrđeno da obojenost nastaje pri pH vrednostima ispod 12,5. Dobijena boja je korišćena za farbanje multifiber tkanine sastavljene od različitih supstrata uključujući diacetat celuloze, beljeni pamuk, poliamid, poliester, akril, svilu, viskozu i vunu. Preliminarni rezultati su pokazali da se boja može uspešno koristiti za bojenje materijala na bazi svile i vune.Di- and tryarylmethine dyes (earlier di- and tryarylmethane dyes) are characterized by the
presence of sp2
-hybridized central carbon atom which leads to the planarity of the molecule. The
planarity in combination with π-conjugation enables the absorption of the light in the visible part of
the spectrum, which gives a molecule a specific color. Such coloration can be transferred to a substrate (textile material) by the adsorption process. In this work tryarylmethine dye was prepared by
the oxidation of the corresponding tryarylmethane. The tryarylmethane was prepared from 4-dimethylaminobenzaldehyde and antipyrine using several procedures: solvent free synthesis using zinc
chloride, solvent free synthesis using p-toluenesulfonic acid and synthesis using hydrochloric acid.
The obtained tryarylmethane was then oxidized using iron(III) chloride to produce tryarylmethine
dye. The obtained molecules were characterized by melting point, 1
H NMR, FT-IR, and mass spectroscopy. In addition, UV-Vis analysis of the dye was performed in organic solvents as well as in aqueous
solutions of different pH. It was confirmed that the coloration occurs at pH below 12.5. The obtained
dye was used for dyeing a multifiber fabric composed of different substrates including diacetate,
bleached cotton, polyamide, polyester, acrylic, silk, viscose and wool. The preliminary results indicated that the dye can be successfully used for dyeing silk and wool material
Probabilistic dietary exposure and risk ranking of pesticides in peppers (Capsicum annuum): Regional and consumer group variability
No full textPesticide residues in peppers (Capsicum annuum) and associated health risks were assessed for populations from different regions and various consumer groups. The QuEChERS protocol combined with LC-MS/MS and GC–MS/MS demonstrated satisfactory linearity (r2 = 0.9929–0.9985), recovery (82.3–117 %), and precision (RSD ≤ 15.3 %), aligning with EU guidelines. Of 197 analyzed pepper samples, 27 % were positive, and 14 % contained multiple residues. Residue levels for 31 detected pesticides ranged from 0.02 mg/kg to 0.94 mg/kg. Risk ranking identified seven pesticides with high-risk scores (>20), notably methiocarb, formetanate, and chlorpyrifos. Chronic dietary exposure index (HIc) indicated no long-term health risks across all population groups, including children and pregnant women. However, acute exposure exceeded the threshold (HIa > 1) in certain samples, particularly for children, suggesting a potential short-term risk, particularly in certain regions. Sensitivity analysis showed that body weight and ingestion rate were the most influential exposure parameters affecting risk estimates
Determination of the Corrosion and Biocompatibility Properties of As-Cast TiNi Alloys
No full textIn this study, a TiNi alloy with a composition of 50 at.% of titanium and 50 at.% of nickel is investigated in terms of its corrosion and biocompatibility behavior for biomedical applications. The corrosion measurements, which include the determination of open-circuit potential and linear polarization resistance measurements, cyclic polarization measurements, and electrochemical impedance spectroscopy in 9 g L−1 NaCl, show that TiNi has satisfactory corrosion stability. According to the SEM and EDS analysis, after cyclic polarization, pitting corrosion occurred, accompanied by the dissolution of the unstable Ti2Ni inclusions. The analysis also showed that TiNi has good biocompatibility for human osteoblast-like cells, as determined by the mitochondrial activity, which was assessed using a direct contact test following ISO standard 10993-5, via scanning electron microscopy (SEM) and fluorescent microscopy