Suvakeen Amala Doss.Hebciba Mary1*, Karunaivel Kavipriya2, Senthil Vadivelan, Anu Ratthika1, Thammanan Vidhya1, Arulanandam.JerleenSindhuja1, Nilavan Anitha1, Ramasamy Srinivasan3, SusaiRajendran1,4,Thiruvenkadam Gowrani5
1PG Department of Chemistry, Research Centre, St Antony’s College of Arts and Sciences for Women, Amala Annai Nagar, Tamaraipadi, Dindigul, (Affiliated to Mother Teresa Women’s University, Kodaikanal ), Tamilnadu, India,2Department of Chemistry, PSNA College of Engineering and Technology, Dinidgul, India, 3Tamilnadu State Council for Science and Technology, DOTE campus, Chennai, India, 4Centre for Nanoscience and Technology, Pondicherry University, Puducherry, India..5Department of Chemistry,Nallamuthu Gounder Mahalingam College, Pollachi, India
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302119A
Zastita Materijala 64 (2)
119 – 133 (2023)
Influence of dilution and addition of soda water on the corrosion resistance of orthodontic wires immersed in artificial saliva in presence of Copper Barrel, a hard drink
Abstract
Copper barrel brandy can be taken orally with dilution of bisleri water or soda water and without dilution. People clipped with orthodontic wires may take copper barrel brandy orally, with dilution of without dilution. How far theorthodontic wires will be affected by these items? To find an answer the present research work is undertaken.Corrosion resistance of orthodontic wires made of Ni-Ti alloy and Ni-Cr alloy in artificial saliva in the absence and presence of copper barrel, water and soda water has been evaluated by AC impedance spectra. It is generally observed that Ni-Ti alloy is more corrosion resistant than Ni-Cr alloy in artificial saliva in the presence of copper barrel, water and soda water. When orthodontic wire made of Ni-Ti is immersed in artificial saliva, the charge transfer resistance (Rt) value is 31945Ohmcm2. When it is immersed in copper barrel + artificial saliva (AS) system, Rtvalue increase to 80000Ohmcm2. When it is immersed in soda water + artificial saliva (AS) system, Rtvalue increase to 76450Ohmcm2. When it is immersed in water + artificial saliva (AS) system, Rtvalue increase to 82620Ohmcm2. On the other hand, when orthodontic wire made of Ni-Cr is immersed in artificial saliva, the charge transfer resistance (Rt) value is 80930Ohmcm2. When it is immersed in copper barrel + artificial saliva (AS) system, Rtvalue decrease to 11104Ohmcm2. When it is immersed in soda water + artificial saliva (AS) system, Rtvalue decrease to 10437Ohmcm2. It implies that the people who have been clipped with orthodontic wire made of Ni-Ti alloy can take copper barrel in any form, namely, with dilution or without dilution. The people who have been clipped with orthodontic wire made of Ni-Cr alloy should avoid taking copper barrel in any form, namely, with dilution or without dilution.
Keywords:orthodontic wires, corrosion resistance, soda water, artificial saliva, a hard drink, Ni-alloys
Uticaj razblaživanja i dodavanja soda vode na otpornost na koroziju ortodontskih žica potopljenih u veštačku pljuvačku u prisustvu copper barrel-a, žestokog pića
Izvod
Žestoko piće Copper Barrel može se uzimati oralno sa razblaženjem soda vodom i bez razblaživanja. Ljudi, koji u ustima maju ortodontske žice, koriste ovo žestoko piće oralno, uz razblaživanje i bez razblaživanja. Koliko će ovo piće uticati na ortodontske žice? U cilju pronalaženja odgovora uradjen je ovaj istraživački rad. Otpornost na koroziju ortodontskih žica od legure Ni-Ti i legure Ni-Cr u veštačkoj pljuvački u odsustvu i prisustvu rakije, vode i soda vode je procenjena spektrima AC impedanse. Generalno se primećuje da je legura Ni-Ti otpornija na koroziju od legure Ni-Cr u veštačkoj pljuvački u prisustvu navedenog žestokog pića, vode i soda vode. Kada se ortodontska žica napravljena od Ni-Ti uroni u veštačku pljuvačku, vrednost otpora prenosa naelektrisanja (Rt) iznosi 31945 Ohmcm2. Kada je legura uronjena u žestoko piće + sistem veštačke pljuvačke (AS), vrednost Rt se povećavana 80000 Ohmcm2. Kada je uronjen u sistem soda voda + veštačka pljuvačka (AS), vrednost Rt se povećavana 76450 Ohmcm2. Kada je uronjen u sistem voda + veštačka pljuvačka (AS), vrednost Rt se povećava na 82620 Ohmcm2. S druge strane, kada se ortodontska žica napravljena od legure Ni-Cr uroni u veštačku pljuvačku, vrednost otpora prenosa naelektrisanja (Rt) iznosi 80930 Ohmcm2. Kada je legura uronjena u žestoko piće + sistem veštačke pljuvačke (AS), vrednost Rt se smanjuje na 11104 Ohmcm2. Kada se potopi u sistem soda voda + veštačka pljuvačka (AS), vrednost Rt se smanjuje na 10437 Ohmcm2. To podrazumeva da ljudi koji su imali u ustima ortodontskužicu od Ni-Ti legure mogu da uzimaju navedeno žestoko piće u bilo kom obliku, sa razblaženjem ili bez razblaživanja. Osobe koje su imale u ustima ortodontsku žicu od legure Ni-Cr treba da izbegavaju uzimanje navedenog žestokog pića u bilo kom obliku, sa razblaženjem ili bez razblaženja.
Ključne reči: ortodontske žice, otpornost na koroziju, soda voda, veštačka pljuvačka, žestoko piće, Ni-legure
Hadi Ebrahim Fathabadi, Mohammad Ghorbani*
Sharif University of Technology, Materials Science and Engineering Department, Tehran, Iran
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302134F
Zastita Materijala 64 (2)
134 – 152 (2023)
Investigation of the corrosion inhibition properties of hexamine (HMTA) for mild steel in NaCl solution
Abstract
An effective corrosion inhibitor for steel is Hexamine (HMTA). There have been few studies on its corrosion-inhibiting characteristics, particularly in NaCl solution. The electrochemical characteristics of HMTA performance in NaCl 3.5 wt% solution were examined during this study. Additionally, the properties of the HMTA film on the steel surface was investigated. When tested in NaCl solution, electrochemical results revealed that HMTA is a very efficient corrosion inhibitor for mild steel, with an efficacy of 92% at a concentration of 0.08 M. HMTA exhibited mixed type activity in terms of inhibition, according to the findings. Due to the physical adsorption of HMTA compound, as shown by the XRD results, an organic layer was formed as a strategy for HMTA inhibition. Adsorption of chloride ions as a corrosive factor is reduced by the HMTA films, according to EDS and thermodynamic studies.
Keywords: Hexamine (HMTA), corrosion inhibition, mild steel, NaCl solution.
Istraživanje svojstava inhibicije korozije heksamina (HMTA) za meki čelik u rastvoru NaCl
Izvod
Efikasan inhibitor korozije za čelik je heksamin (HMTA). Bilo je nekoliko studija o njegovim karakteristikama inhibiranja korozije, posebno u rastvoru NaCl. Tokom ovog istraživanja ispitivane su elektrohemijske karakteristike performansi HMTA u rastvoru NaCl 3,5 tež.%. Pored toga, ispitivana su svojstva HMTA filma na površini čelika. Kada su testirani u rastvoru NaCl, elektrohemijski rezultati su otkrili da je HMTA veoma efikasan inhibitor korozije za meki čelik, sa efikasnošću od 92% u koncentraciji od 0,08 M. HMTA je pokazao aktivnost mešovitog tipa u smislu inhibicije, prema nalazima. Zbog fizičke adsorpcije HMTA jedinjenja, kao što pokazuju rezultati XRD, formiran je organski sloj kao strategija za inhibiciju HMTA. HMTA filmovi smanjuju adsorpciju hloridnih jona kao korozivnog faktora, prema EDS i termodinamičkim studijama.
Ključne reči: heksamin (HMTA), inhibicija korozije, meki čelik, rastvor NaCl
Esmeralda Halo, Jonida Tahiraj, Bledar Murtaj,
Sonila Kane, Elda Marku, Aurel Nuro*
Tirana University, Faculty of Natural Sciences, Department of Chemistry, Tirana, Albania
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302153H
Zastita Materijala 64 (2)
153 – 160 (2023)
Analyzes of hydrocarbons (PAH, alkanes and BTEX) in marine
water of Vlora’s port
Abstract
In this study, levels of polycyclic aromatic hydrocarbons (PAH), aliphatic hydrocarbons (n-alkanes) and volatile hydrocarbons were determined in water samples of the port of Vlora which is the second largest port in Albania. It is located in Vlora Bay, near Vlora city. Presence of these pollutants in port area is mainly because of ships transport, commercial/passengers processing and the water currents in-side/out-side the port area. Hydrocarbons (PAHs, n-alkanes and BTEX) are generated mainly by the transport (automobiles, ships, trains, etc), extracting/processing of oil industry, coal mine and other industries. Forest burning and their natural background make them very often in environment.
Water samples were taken in May 2022 in different stations of the Vlora’s port (inside and outside its area). Aromatic and aliphatic hydrocarbons were extracted simultaneously using two steps liquid-liquid extraction (LLE) technique. Firstly, dichloromethane (MeCl2) and after that n-hexane were used as extraction solvents. After extraction, the organic phase was dried with sodium sulfate anhydrous, for water removing. “Clean-up” procedure was realized in an alumina column. After the concentration to 2 ml, the samples were injected in Varian 450 GC equipped with FID detectors. BTEX were analyzed using head space solid phase micro-extraction technique (HS/SPME) by using polydimethylsiloxane fiber (PDMS) followed by GC/FID technique.
PAH, n-alkanes and BTEX were found almost in all water samples of Vlora’s port. Their presence could be because of anthropogenic factors (elevated activity and ship transport) in the port area. The levels of hydrocarbons in water samples of Vlora’s port were higher / comparable than reported levels for them in other stations of the Adriatic Sea, Albania part.
Keywords: Port of Vlora, PAH, n-Alkanes, BTEX, Water analyze, GC/FID
Analize ugljovodonika (PAH, alkana i BTEX) u morskoj vodi luke Valona
Izvod
U ovoj studiji utvrđeni su nivoi policikličnih aromatičnih ugljovodonika (PAH), alifatičnih ugljovodonika (n-alkana) i isparljivih ugljovodonika u uzorcima vode luke Valona koja je druga najveća luka u Albaniji. Nalazi se u zalivu Valone, u blizini grada Valone. Prisustvo ovih zagađivača u lučkom području je uglavnom zbog transporta brodova, komercijalne/putničke obrade i vodenih tokova unutar/izvan područja luke. Ugljovodonici (PAH, n-alkani i BTEKS) se uglavnom proizvode transportom (automobili, brodovi, vozovi, itd.), vađenjem/preradom naftne industrije, rudnika uglja i drugih industrija. Paljenje šuma i njihova prirodna pozadina čine ih veoma čestim u okruženju.
Uzorci vode uzeti su u maju 2022. godine u različitim stanicama luke Valona (unutar i van njenog područja). Aromatični i alifatični ugljovodonici su ekstrahovani istovremeno korišćenjem tehnike ekstrakcije tečnost-tečnost u dva koraka (LLE). Kao rastvarači za ekstrakciju prvo su korišćeni dihlorometan (MeCl2), a zatim n-heksan. Posle ekstrakcije, organska faza je osušena sa anhidrovanim natrijum sulfatom, radi uklanjanja vode. Procedura „čišćenja“ je realizovana u koloni glinice. Nakon koncentracije do 2 ml, uzorci su ubrizgani u Varian 450 GC opremljen FID detektorima. BTEKS je analiziran korišćenjem tehnike mikro-ekstrakcije čvrste faze (HS/SPME) uz upotrebu polidimetilsiloksanskih vlakana (PDMS), praćeno GC/FID tehnikom.
PAH, n-alkani i BTEKS pronađeni su skoro u svim uzorcima vode luke Valona. Njihovo prisustvo može biti zbog antropogenih faktora (povećana aktivnost i brodski transport) u području luke. Nivoi ugljovodonika u uzorcima vode luke Valona bili su viši/uporedivi od prijavljenih nivoa za njih u drugim stanicama Jadranskog mora, deo Albanije.
Ključne reči: Luka Valona, PAH, n-alkani, BTEKS, analiza vode, GC/FID
Isaev Doniyor Toshbotirovich*
Navoi state university of mining and technologies, Navoi city, Uzbekistan
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302161T
Zastita Materijala 64 (2)
161 – 169 (2023)
Ion nitriding and surface alloying of H13A hard alloy cutting tools
Abstract
Ion-plasma coatings are widely used to increase the wear resistance of hard alloy metalworking tools. However, plasma coatings are practically not combined with other technological operations and do not improve the physical and mechanical properties of tool working elements. Hardening tools made of hard alloys is one of the promising directions that is created by layered structures on the surface. It provides a gradient distribution of physical and chemical properties between the wear-resistant coating and the base material.
Keywords: cutting tool, carbide insert, zirconium, niobium alloy, electron-beam alloying, netrided, tool failure.
Jonsko nitriranje i površinsko legiranje reznih alata od tvrde legure H13A
Izvod
Jonsko-plazma premazi se široko koriste za povećanje otpornosti na habanje alata za obradu metala od tvrdih legura. Međutim, plazma premazi se praktično ne kombinuju sa drugim tehnološkim operacijama i ne poboljšavaju fizičko-mehanička svojstva radnih elemenata alata. Kaljenje alata od tvrdih legura je jedan od perspektivnih pravaca koji se stvara slojevitim strukturama na površini. Obezbeđuje gradijentnu distribuciju fizičkih i hemijskih svojstava između premaza otpornog na habanje i osnovnog materijala.
Ključne reči: Rezni alat, karbidni umetak, cirkonijum, legura niobijuma, legiranje elektronskim snopom
Anitha Nilavan1, Little Jewelcy Arockiaraj1*, Arputha Anucia Thomas Antony1, Jeevitha Clara Micheal Velankanni1, Jeyalakshmi Rajendran1, Roslin Arockiam1, Pushpa Murugesh1, Veerapandian Velkannan2, Gurmeet Singh3, Abdulhameed Al-Hashem4, Susai Rajendran1,5, Arjunan Krishnaveni6
1Department of Chemistry, Corrosion Research Centre, St. Antony’s College of Arts and Sciences for Women, Dindigul-624005(Mother Teresa Women’s University,Kodaikanal, India), 2Department of Chemistry, Thiagarajar College of Engineering, Thiruparankundram, Madurai, Tamil Nadu, India, 3Vice Chancellor, Pondicherry University, Puducherry, India, 4Petroleum Research Centre, Kuwait Institute for Scientific Research, Kuwait, 5Adjunct Professor, Centre for Nanoscience and Technology, Pondicherry University, Puducherry, India, 6Department of Chemistry, Yadava College, Madurai, Tamil Nadu, India.
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302170N
Zastita Materijala 64 (2)
170 – 176 (2023)
Corrosion resistance of mild steel immersed in simulated concrete pore solution in the presence of sodium potassium tartrate
Abstract
The corrosion resistance of mild steel in simulated concrete pore solution (SCPS) in the absence and presence of sodium potassium tartrate (SPT) has been investigated by polarization technique and AC impedance spectra. The present study leads to the following conclusions. Polarization study reveals that sodium potassium tartrate system functions as anodic type of inhibitor. AC impedance spectra reveal that a shielding film is formed on the metal surface. When mild steel is used as rebar, sodium potassium tartrate may be mixed with concrete. Thus the mild steel will be protected from corrosion. The protective film consists of ferrous tartrate complex formed on metal surface. In the presence of sodium potassium tartrate the linear polarisation resistance increases from 226 Ohmcm2 to 455 Ohmcm2, corrosion current decreases from 1.901×10-4A/cm2 to1.096 x10-4A/cm2, charge transfer resistance (Rt) increases from 49 Ohmcm2 to 77 Ohmcm2, impedance increases from 1.807 to 2.084, phase angle increases from 33.92° to 35.31° and double layer capacitance (Cdl) value decreases from 1.040×10-7F/cm2 to 0.662 x10-7F/cm2. Corrosion potential shifts from -973 mV/SCE to -867 mV/SCE .This confirms that the inhibitor system functions as anodic type of inhibitor controlling anodic reaction predominantly. This formulation may find application in concrete technology. This may be used in the construction of bridges and concrete structures.
Keywords: sodium potassium tartrate, corrosion resistance, mild steel, simulated concrete pore solution, electrochemical studies, electrochemical impedance spectra
Otpornost na koroziju mekog čelika uronjenog u simulirani rastvor betonskih pora u prisustvu natrijum-kalijum tartarata
Izvod
Otpornost mekog čelika na koroziju u simuliranom rastvoru pora betona (SCPS) u odsustvu i prisustvu natrijum-kalijum tartarata (SPT) je ispitana tehnikom polarizacije i spektrom impedanse naizmenične struje. Studija polarizacije otkriva da sistem natrijum-kalijum tartrata funkcioniše kao anodni tip inhibitora. Spektri impedanse naizmenične struje otkrivaju da se na površini metala formira zaštitni film. Kada se kao armatura koristi meki čelik, natrijum-kalijum tartarat se može mešati sa betonom. Tada će meki čelik biti zaštićen od korozije. Zaštitni film se sastoji od kompleksa ferotartarata formiranog na metalnoj površini. U prisustvu natrijum-kalijum tartarata, otpor linearne polarizacije raste sa 226 Ohmcm2 na 455 Ohmcm2, struja korozije se smanjuje sa 1,901k10-4 A/cm2 na 1,096 k10-4A/cm2, otpor prenosa naelektrisanja (Rt) raste sa 49 Ohmcm2 na 77 Ohmcm2, impedansa se povećava sa 1,807 na 2,084, fazni ugao se povećava sa 33,92° na 35,31° i vrednost kapacitivnosti dvostrukog sloja (Cdl) se smanjuje sa 1,040k10-7 F/cm2 na 0,662 k10-7 F/cm2. Potencijal korozije se pomera sa -973 mV/SCE na -867 mV/SCE. Ovo potvrđuje da inhibitorni sistem funkcioniše kao anodni tip inhibitora koji kontroliše anodnu reakciju pretežno. Ova formulacija može naći primenu u tehnologiji betona. Ovo se može koristiti u izgradnji mostova i betonskih konstrukcija.
Ključne reči: natrijum-kalijum tartarat, otpornost na koroziju, meki čelik, simulirani rastvor pora betona, elektrohemijska ispitivanja, spektri elektrohemijske impedanse
Lyudmila Nyrkova*, Anatolii Rybakov, Larysa Goncharenko, Svetlana Osadchuk, Yulia Kharchenko
E.O Paton Electric Welding Institute of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302177N
Zastita Materijala 64 (2)
177 – 189 (2023)
Analysis of the causes of fracture of the main gas pipeline
Abstract
A complex of research has been conducted to establish the causes of the accident of the main gas pipeline made of 1420×15.7 mm X70 steel after 20 years of operation. It is found that pipe destruction was initiated by the longitudinal crack with a length of 470 mm and a maximum depth of 6.8 mm, oriented in the direction of the pipe and perpendicular to the outer surface of the pipe identified as stress-corrosion cracking. The crack initiation is due to the disboundment of the tape protection coating, the high corrosion activity of the soil, and the complex stress-strain state caused by deviations from the design objectives during construction. The chemical composition the base metal of all investigated pipes corresponds to the requirements of the technical conditions for steel pipes in category X70; pipes welding are performed with the typical materials used in pipe welding plants. Despite the differences, the structural and mechanical characteristics (yield strength, ultimate strength, and impact strength) of the steel and weld metal of the studied pipes are identical. The relative elongation (δ5) of the operated pipes is below the normalized values, but, it is necessary to take into account the possibility of deviations in these characteristics of steel in the initial state. Significant reserves of toughness indirectly indicate low damage of metal and, accordingly, satisfactory resistance to destruction of the metal of the studied pipes.
Keywords: main pipeline, Х70 steel, microstructure, mechanical properties, stress-corrosion cracking, cathodic protection
Analiza uzroka loma magistralnog gasovoda
Izvod
Sproveden je kompleks istraživanja za utvrđivanje uzroka havarije magistralnog gasovoda od čelika 1420×15,7 mm X70 nakon 20 godina rada. Utvrđeno je da je destrukciju cevi inicirala uzdužna pukotina dužine 470 mm i maksimalne dubine 6,8 mm, orijentisana u pravcu cevi i okomita na spoljašnju površinu cevi koja je identifikovana kao prslina od naponske korozije. Nastanak pukotine je usled odvajanja zaštitnog premaza trake, visoke aktivnosti korozije tla i složenog naponsko-deformacionog stanja uzrokovanog odstupanjima od projektnih ciljeva tokom izgradnje. Hemijski sastav osnovnog metala svih ispitivanih cevi odgovara zahtevima tehničkih uslova za čelične cevi kategorije X70; zavarivanje cevi se izvodi tipičnim materijalima koji se koriste u postrojenjima za zavarivanje cevi. Uprkos razlikama, strukturne i mehaničke karakteristike (napor tečenja, krajnja čvrstoća i udarna čvrstoća) čelika i metala šava ispitivanih cevi su identične. Relativno izduženje (δ5) ispitivanih cevi je ispod normalizovanih vrednosti, ali je potrebno uzeti u obzir mogućnost odstupanja ovih karakteristika čelika u početnom stanju. Značajne rezerve žilavosti indirektno ukazuju na nisko oštećenje metala i, shodno tome, na zadovoljavajuću otpornost na destrukciju metala ispitivanih cevi.
Ključne reči: magistralni cevovod, čelik X70, mikrostruktura, mehanička svojstva, naponsko-koroziono pucanje, katodna zaštita
Ejeagba Okorie Imo*1, Chinedu Emeka Ihejirika2,
Adaugo Goodness Ndukaku1, Peter James Misoni1
1Federal University of Technology, Department of Microbiology, Owerri, Nigeria, 2Federal University of Technology, Department of Environmental Management, Owerri, Nigeria
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302190I
Zastita Materijala 64 (2)
190 – 197 (2023)
Effects of Desulfotomaculum sp on corrosion behaviour of mild steel
and aluminium in sea water
Abstract
The microbiologically influenced corrosion of mild steel and aluminum in sea water (SW) caused by a sulfate reducing bacterium (SRB), Desulfotomaculum sp was investigated. The corrosion rates were evaluated at intervals of ten days for a period of sixty days using gravimetric and electrochemical methods. Results showed that corrosion rate decreased with exposure time after initial increase. The plot of the electrode potential (EP) with the exposure time shows a decrease as resistance increased due to the corrosion product formed on the surface of the metals. Aluminum recorded a maximal EP reduction (-0.85 mV) after 60 days of incubation, with an onset potential of -0.53 mV after 10 days. The more negative the EP, the greater the tendency to form ions and hence to corrode. The average corrosion rate of mild steel and aluminum coupons in the presence of SRB was 4-fold higher compared to coupons on media without Desulfotomaculum sp.
Keywords: Microbiologically influenced corrosion, Corrosion rate, Electrode potential, SRB, Passivity, Metal
Efekti Desulfotomaculum sp na korozijsko ponašanje mekog čelika i aluminijuma u morskoj vodi
Izvod
Mikrobiološki uticaj na koroziju mekog čelika i aluminijuma u morskoj vodi (SV) prouzrokovane bakterijom za smanjenje sulfata (SRB), istražena je Desulfotomaculum SP. Stope korozije procenjene su u intervalima od deset dana u periodu od šezdeset dana koristeći gravimetrijske i elektrohemijske metode. Rezultati su pokazali da se stopa korozije smanjila sa vremenom izlaganja nakon početnog povećanja. Plot potencijala elektroda (EP) sa vremenom izloženosti prikazuje smanjenje kao otpor porastao zbog korozije koji se formira na površini metala. Aluminijum je zabiležio maksimalnu redukciju EP (-0,85 MV) nakon 60 dana inkubacije, sa početnim potencijalom od -0,53 mV nakon 10 dana. Što je više negativnije, to je veća tendencija da formiraju jone i samim tim da korodiraju. Prosečna stopa korozije mekog čelika i aluminijuma u medijima u prisustvu SRB-a bila je 4-puta više u poređenju na medije bez Desulfotomaculum Sp.
Ključne reči: mikrobiološki uticaja na koroziju, stopu korozije, potencijal elektroda, SRB, pasivnost, metal
Jovan P. Šetrajčić1, Siniša M. Vučenović2,
Stevo K. Jaćimovski3
1Academy of Sciences and Arts of the Republic of Srpska, Banja Luka, Republic of Srpska – Bosnia and Herzegovina, 2University of Banja Luka, Faculty of Natural Sciences and Mathematics, Banja Luka, Republic of Srpska – Bosnia and Herzegovina,3University of Criminal Investigation and Police Studies, Zemun – Belgrade, Serbia
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302198S
Zastita Materijala 64 (2)
198 – 203 (2023)
Elementary particle microstates in sandwich nanostructures
Abstract
This paper analyzes micro-characteristics (single-particle wave functions, the dispersion law of elementary excitations) of sandwich structures. Such structures have exceptional properties and have become current issues in the light of relatively recent discoveries in crystalline structures such as boron nitride-graphene-boron nitride. In our case, structures with a simple cubic lattice are analyzed, but the results can be applied to the structures with monoclinic and triclinic lattices.
Keywords: Sandwich structure, one-particle wave function, dispersion law of elementary excitations.
Mikrostanja elementarnih čestica u sendvič nanostrukturama
Izvod
U ovom radu se analiziraju mikrokarakteristike (jednočestične talasne funkcije, zakon disperzije elementarnih pobuđenja) sendvič struktura. Takve strukture imaju izuzetna svojstva i postale su aktuelna u svetlu relativno nedavnih otkrića u kristalnim strukturama kao što su bor nitrid-grafen-bor nitrid. U našem slučaju se analiziraju strukture sa jednostavnom kubičnom rešetkom, ali se rezultati mogu primeniti na strukture sa monokliničkim i trikliničkim rešetkama.
Ključne reči: Sendvič strukture, jednočestična talasna funkcija, zakon disperzije elementarnih ekscitacija.
Paul A. Andoor*, Kelechukwu B. Okeoma,
Uchenna S. Mbamara
Federal University of Technology, Department of Physics, Owerri, Nigeria
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302204A
Zastita Materijala 64 (2)
204 – 212 (2023)
Adsorption inhibitive properties of Rosmarinus officinalis L. on aluminium AA8011 Alloy in 1.0M HCl
Abstract
The adsorption mechanism of Rosmarinus officinalis L. as corrosion inhibitor for Al AA8801 alloy in 1.0M HCl was studied using gravimetric method and thermodynamics studies at 303, 313, 323 and 333K. Inhibitor concentrations ranged between 0 and 1000mg/L. Results show that the adsorption mechanism of Rosmarinus officinalis L. is via physisorption, generally endothermic and accompanied by a resulting decrease in disorder. Inhibitor efficiency largely decreased with increase in temperature, and decrease in concentration of the extract. The presence of an external magnetic field enhanced the dissolution of passivating Al2O3 films, thereby increasing corrosion rate.
Keywords: aluminum; weight loss; acid corrosion; langmuir; magnetic field
Inhibitorska svojstava ekstrakta Rosmarinus officinalis L. na koroziju legure aluminijuma AA8011 u 1,0M HCl
Izvod
Mehanizam adsorpcije Rosmarinus officinalis L. kao inhibitora korozije legure Al AA8801 u 1,0 M HCl proučavan je gravimetrijskom metodom i termodinamičkim studijama na 303, 313, 323 i 333 K. Koncentracije inhibitora su se kretale između 0 i 1000 mg/L. Rezultati pokazuju da se mehanizam adsorpcije Rosmarinus officinalis L. odvija putem fizisorpcije, generalno endotermne i praćena je rezultirajućim smanjenjem poremećaja. Efikasnost inhibitora je u velikoj meri opadala sa povećanjem temperature i smanjenjem koncentracije ekstrakta. Prisustvo spoljašnjeg magnetnog polja pojačalo je rastvaranje pasivizirajućih Al2O3 filmova, čime je povećana brzina korozije.
Ključne reči: aluminijum, gubitak težine, korozija, Langmuir, magnetno polje
Shiva Sabzandam1, Masoumeh Zahmatkeshan 2,3*, Moein Adel2,4, Mehrad Mehrdadian5, Farzaneh Saliminia3, Fariba Esmaeili6
1Islamic Azad University, Department of Medical Nanotechnology, Faculty of Advanced Sciences and Technology, Tehran Medical Sciences, Tehran, Iran, 2Iran University of Medical Sciences, Cellular and Molecular Research Center, Tehran, Iran, 3Iran University of Medical Sciences, Department of Medical Nanotechnology, Faculty of Advanced Technologies in Medicine, Tehran, Iran, 4Tabriz University of Medical Sciences, Department of Medical Nanotechnology, Tabriz, Iran, 5Iran University of Medical Sciences, School of Medicine-International Campus, Tehran, Iran, 6Tehran University of Medical Sciences, Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran, Iran
Scientific paper
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2302213S
Zastita Materijala 64 (2)
213 – 222 (2023)
Investigating the therapeutic effect of folic acid conjugated ZnO nanoparticles on human triple negative breast cancer cell line
Abstract
Triple-negative breast cancer (TNBC) accounts for 15-20% of all invasive breast cancers and has a poor prognosis. ZnO NPs are promising anti-cancer agents. Moreover, folate alpha receptor (FRα) is a potential biomarker and therapeutic target because it is significantly expressed in TNBC. Therefore, ZnO and folic acid-conjugated ZnO (F-ZnO) NPs were synthesized by the sol-gel method. NPs were characterized by DLS, zeta potential, TEM, FTIR, and ICP-MS. FA-ZnO NPs had a mean diameter of 20 ± 2 nm and a surface charge of -15 mV, while ZnO NPs had a mean diameter of 40 ± 5 nm and a surface charge of -5 mV. The MTT assay and trypan blue test, respectively, were used to determine the cytotoxicity and viability percentage of ZnO and F-ZnO NPs at different concentrations of 2, 4, 8, 16, 32, 64 and 128 µg/mL for 12, 24, 48 and 72 hours (h) on the human TNBC cell line MDA-MB-231. The results indicated that both ZnO and F-ZnO NPs significantly reduced the viability of the cancer cells in a dose-dependent and time-dependent manner (p<0.05). The IC50 values for FA-ZnO NPs were approximately 3, 3.74, 4.38 and 5.5 times higher than those for ZnO NPs at 12-, 24-, 48- and 72-hour time points, respectively. The results suggest that F-ZnO NPs have the potential to be a good option for TNBC treatment and warrant further investigations.
Keywords: Nanoparticle, Zinc oxide, Folic acid, Triple negative breast cancer.
Istraživanje terapeutskog efekta nanočestica ZnO konjugovanih sa folnom kiselinom na trostruko negativnu ćelijsku liniju raka dojke kod ljudi
Izvod
Trostruko negativan rak dojke (TNBC) čini 15-20% svih invazivnih karcinoma dojke i ima lošu prognozu. ZnO NPs su obećavajući agensi protiv raka. Štaviše, folatni alfa receptor (FRa) je potencijalni biomarker i terapeutska meta jer je značajno izražen u TNBC. Zbog toga su ZnO i ZnO (F-ZnO) NPs konjugovani sa folnom kiselinom sintetisani sol-gel metodom. NP su karakterisali DLS, zeta potencijal, TEM, FTIR i ICP-MS. FA-ZnO NPs su imali srednji prečnik od 20 ± 2 nm i površinsko naelektrisanje od -15 mV, dok su ZnO NPs imali srednji prečnik od 40 ± 5 nm i površinsko naelektrisanje od -5 mV. MTT test i tripan plavi test, respektivno, korišćeni su za određivanje procenta citotoksičnosti i vitalnosti ZnO i F-ZnO NPs pri različitim koncentracijama od 2, 4, 8, 16, 32, 64 i 128 µg/mL za 12, 24 , 48 i 72 sata (h) na humanoj TNBC ćelijskoj liniji MDA-MB-231. Rezultati su pokazali da i ZnO i F-ZnO NPs značajno smanjuju vitalnost ćelija karcinoma na način koji zavisi od doze i vremena (p<0,05). Vrednosti IC50 za FA-ZnO NPs bile su približno 3, 3,74, 4,38 i 5,5 puta veće od onih za ZnO NPs u vremenskim tačkama od 12, 24, 48 i 72 sata, respektivno. Rezultati sugerišu da F-ZnO NPs imaju potencijal da budu dobra opcija za tretman TNBC-a i da opravdavaju dalja istraživanja.
Ključne reči: nanočestica, cink oksid, folna kiselina, trostruko negativni rak dojke.