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Zaštita Materijala 3. 2022

Vukoman Jokanović1,2, Slavoljub Živković3

1ALBOS doo, Beograd, Serbia, 2University of Belgrade, Institute of Nuclear Sciences “Vinča”, Belgrade, Serbia, 3School of Dentistry, Belgrade, Serbia

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203221J

Zastita Materijala 63 (3)
221 – 229 (2022)

 

Controversies related to real protection against SARS- CoV-2 virus of the most frequently used face masks

Abstract

Face masks serve to protect the respiratory system from unwanted aerosol droplets, in which various types of pathogens or pollutants are present. They are particularly important during a pandemic, like SARS-CoV-2 pandemic we are withessing. The efficiency of filtration of aerosol droplets, which contain the virus particles, is generally unsatisfactory, especially in conditions of extremely virulent environments, for the most of commercially available masks. Therefore, the challenge is to produce masks with increased filtration efficiency, in order to reduce the percentage of virus penetration through the mask. Hence, it is crucial to correctly define the possibilities and limitations of today’s most commonly used epidemiological masks, in order to successfully define completely new concepts of face masks manufacturing, which would enable the most effective protection not only of medical workers but also patients, especially in areas where virus concentrations are extremely high. Also, it has been shown that, in addition to the concentrations of infectious pathogens in a given environment, the conditions in which infection with a given pathogen occurs, such as temperature and humidity within a given contaminated space, are also important.

Keywords: face mask, nanoparticles, filtration efficiency, aerosol transfer mechanism, SARS-Cov-2, cotton canvas.

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Kontroverze u vezi sa stvarnom zaštitom od virusa SARS-CoV-2 različitim najčešće korišćenim maskama

Izvod

Maske za lice služe da zaštite respiratorni sistem od neželjenih kapljica aerosola, u kojima su prisutne razne vrste patogena ili zagađivača. Posebno su važne tokom neke pandemije, kao što je pandemija SARS-CoV-2 virusa, kokoj smo svedoci.. Efikasnost filtracije kapljica aerosola koje sadrže virus kod većine komercijalno dostupnih maski je uglavnom nezadovoljavajuća, posebno u uslovima ekstremno virulentnih sredina. Stoga je izazov proizvesti maske sa povećanom efikasnošću filtracije, kako bi se smanjio procenat prodiranja virusa kroz masku. Zbog toga je ključno precizno definisati mogućnosti i ograničenja današnjih najčešće korišćenih epidemioloških maski, da bi se uspešno definisali potpuno novi koncepti proizvodnje maski za lice, koji bi omogućili što delotvorniju zaštitu ne samo medicinskih radnika, već i pacijenata, posebno kada se nalaze u područjima gde je koncentracija virusa izuzetno visoka. Takođe, pokazano je da su pored koncentracije infektivnih patogena u datoj sredini važni i uslovi u kojima dolazi do infekcije datim patogenima, kao što su temperatura i vlažnost unutar datog kontaminiranog prostora.

Ključne reči: maska za lice, nanočestice, efikasnost filtracije, mehanizam prenosa aerosola, SARS-Cov-2, pamučno platno.

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Palanichamy Satyabama1*,Nellainayagam Narendran2, Karuyppiah Bavithra Devi3, Thiruppathi Raja Uma Sankareswari4, Anita Nilavan5, Susai Rajendran5,6,
Caslav Lacnjevac7

1Visting Faculty, Department of Chemistry, Anna University – University College of Engineering, Dindigul, Tamilnadu, India, 2PSNA College of Engineering and Technology, Department of Chemistry, Dindigul, India, 3Department of Civil, Anna University,Chennai Tamilnadu, India, 4Department of Chemistry, Rajapalayam Rajus College, Rajapalayam, Tamilnadu, India, 5Department of Chemistry, St. Antony’s College of Arts and Sciences for Women Thamaraipady, Tamil Nadu, India, 6Adjunct Professer, Pondicherry Uniersity, Puducherry, India, 7University of Belgrade, Faculty Agriculture, Belgrade, Serbia

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203230S

Zastita Materijala 63 (3)
230 – 237 (2022)

 

Electrochemical studies on the corrosion behaviour of Aluminium in an alkaline medium

Abstract

Corrosion of Aluminum metal at pH 10 has been controlled by dicarboxylic acids such as oxalic acid (OA) and adipic acid (AA).The Inhibition efficiency (IE) has been determined by the classical weight loss method. The maximum inhibition efficiency (IE) offered by the oxalic acid (OA) and adipic acid (AA) 250 ppm and Zn2+ 50 ppm system are 88 and 96%. To determine the values of Linear Polarization Resistance (LPR) and corrosion Current (Icorr), potentiodynamic polarization study has been used.

Keywords: Aluminium, Oxalic acid, Adipic Acid, electrochemical study.

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ELEKTROHEMIJSKA ISTRAŽIVANJA O KOROZIJSKOM PONAŠANJU ALUMINIJUMA U ALKALNOJ SREDINI

Izvod

Korozija metala aluminijuma na pH 10 je kontrolisana dikarboksilnim kiselinama kao što su oksalna kiselina (OA) i adipinska kiselina (AA). Efikasnost inhibicije (IE) je određena klasičnom metodom gubitka težine. Maksimalna efikasnost inhibicije (IE) koju nude sistem oksalne kiseline (OA) i adipinske kiseline (AA) 250 ppm i Zn2+ 50 ppm iznosi 88% i 96%. Za određivanje vrednosti linearne polarizacione otpornosti (LPR) i struje korozije (Icorr), korišćena je potenciodinamička studija polarizacije.

Ključne reči: aluminijum, oksalna kiselina, adipinska kiselina, elektrohemijska studija.

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Khaled M. Abdel El-Khalek, Kamal Shalabi, Mohamed A. Ismail, Abd El-Aziz S. Fouda*

Mansoura University, Department of Chemistry, Faculty of Science, Mansoura 35516, Egypt

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203238A

Zastita Materijala 63 (3)
238 – 250 (2022)

 

Adsorption and inhibitive impact of 5-[4-(dimethylamino) benzylidene]-1,3-dimethylbarbituric acid on carbon steel corrosion in molar hydrochloric acid solution

Abstract

The inhibiting impact of ecofriendly 5-[4-(dimethylamino) benzylidene]-1,3-dimethylbarbituric acid in 1 M HCl on the corrosion for carbon steel has been examined via “weight loss (WL) method, potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM) tests”. The attained outcomes exhibit that the investigated compound is excellent inhibitor and its inhibition efficiency (%IE) rises by raising concentration and decreases by raising the temperature. The adsorption of 5-arylidene barbituric acid on the surface of C-steel follows Langmuir isotherm. The adsorption process of the investigated compound is spontaneous and considered as of chemisorption and physisorption type. PP curves revealed that the 5-arylidene barbituric acid derivative is mixed-type inhibitor. Moreover, EIS results confirmed the adsorption of the investigated compound on C-steel surface via increasing on charge transfer resistance (Rct). The IE% of this inhibitor reached to 86.9% at concentration 21×10-6 M according to PP method. Finally, the experimental and theoretical results are in good harmony.

Keywords: Carbon steel, HCl, EFM, EIS, 5-Arylidene barbituric acid derivative.

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Adsorpcijski i inhibitorski uticaj 5-[4-(dimetilamino) benziliden] -1,3-dimetilbarbiturne kiseline na koroziju ugljeničnog čelika u molarnom rastvoru hlorovodonične kiseline

Izvod

Inhibicijski uticaj ekološki prihvatljive 5-[4-(dimetilamino) benziliden]-1,3-dimetil barbiturne kiseline u 1M HCl na koroziju ugljeničnog čelika je ispitan pomoću metoda gubitka težine (VL), potenciodinamičke polarizacije (PP), elektrohemijske impedansne spektroskopije (EIS) i testova elektrohemijske frekvencijske modulacije (EFM). Postignuti rezultati pokazuju da je ispitivano jedinjenje odličan inhibitor i da se njegova efikasnost inhibicije (%IE) povećava povećanjem koncentracije i smanjuje povećanjem temperature. Adsorpcija 5-ariliden barbiturne kiseline na površini ugljeničnog čelika prati Langmuirovu izotermu. Proces adsorpcije ispitivanog jedinjenja je spontan i smatra se hemisorpcionim. PP krive su otkrile da je derivat 5-ariliden barbiturne kiseline inhibitor mešovitog tipa. Štaviše, rezultati EIS-a su potvrdili adsorpciju ispitivanog jedinjenja na površini ugljeničnog čelika kroz povećanje otpora prenosa naelektrisanja (Rct). IE% ovog inhibitora dostigao je 86,9% pri koncentraciji 21×10-6 M prema PP metodi. Konačno, eksperimentalni i teorijski rezultati su u dobroj harmoniji.

Ključne reči: ugljenični čelik, HCl, EFM, EIS, derivat 5-ariliden barbiturne kiseline

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Željko Stojanović1*, Sanja Stanisavljev2, Spasoje Erić3

1Šinvoz d..o.o., Zrenjanin, Srbija, 2Univerzitet u Novom Sadu, Tehnički fakultet „Mihajlo Pupin“, Zrenjanin, Srbija, 3Visoka tehnička škola strukovnih studija, Zrenjanin, Srbija

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203251S

Zastita Materijala 63 (3)
251 – 270 (2022)

 

Directions of development and application of plasma nitriding in industry

Abstract

This paper presents a discussion of the results of previous research of the effects of surface modification of structural materials and tool steels using plasma nitriding (PN) in order to improve their mechanical, tribological and corrosion behavior. The paper discusses the current status and future directions in the application of PN on various wearing components that are exposed to high loads, stresses and frequent temperature changes. The paper provides an overview of the relevant literature whose results show the most favorable or optimal parameters of the PN process aimed at achieving the best performance in terms of wear and corrosion resistance and hardness increase for the various materials considered. Systematization of literature data about research of the impact of low-temperature PN on stainless steels has placed emphasis on those process mechanisms that achieve benefits for surface layers without creating negative side effects in the form of loss of corrosion resistance. The strengthening of hot forging dies is considered through the reasons and problems that cause the need for the application of PN, and then paper focuses on the role of PN in achieving the tribological properties required to extend the service life of the die. Publications in which the nitriding of titanium alloys is investigated through the reduction of wear, increase of bearing capacity and microhardness depending on the input parameters of the process, ie the optimal parameters applied in order to obtain the best performance characteristics are cited. The application of PN to aluminum and its alloys is discussed, as well as the conditions of testing and the achieved improvements.

Keywords: plasma nitriding, stainless steels, hot forging die, titanium alloys, aluminium alloys, corrosion, wear

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Pravci razvoja i primene plazma nitriranja u industriji

Izvod

U ovom radu predstavljena je diskusija rezultata dosadašnjih istraživanja efekata površinske modifikacije konstrukcionih materijala i alatnih čelika primenom plazma nitriranja (PN) u svrhu unapređenja njihovog mehaničkog, tribološkog i korozionog ponašanja. U radu se diskutuju trenutni status i budući pravci u primeni PN na raznim habajućim komponentama koje su izložene velikim opterećenjima, naprezanjima i čestim promenama temperature. Rad pruža pregled relevantne literature čiji rezultati prikazuju najpovoljnije, odnosno optimalne parametre procesa PN čiji je cilj postizanje najboljeg učinka u pogledu otpornosti na habanje, koroziju i povećanja tvrdoće za različite razmatrane materijale. Sistematizacija literaturnih podataka o istraživanjima uticaja niskotemperaturnog PN na nerđajuće čelike stavila je akcenat na one mehanizme procesa koji postižu korist za površinske slojeve bez stvaranja negativnih nuspojava u vidu gubitka otpornosti prema koroziji. Ojačavanje kalupa za kovanje u toplom stanju razmatrano je kroz razloge i probleme koji izazivaju potrebu za primenom PN, a zatim se rad fokusira na ulogu PN u postizanju triboloških svojstava potrebnih za produženje radnog veka kalupa. Navode se publikacije u kojima je nitriranje legura titana istraživano kroz smanjenje habanja, povećanje nosivosti i mikrotvrdoće u zavisnosti od ulaznih parametara procesa, odnosno optimalnih parametara primenjenih u svrhu dobijanja najboljih radnih karakteristika. Govori se o primeni PN na aluminijumu i na njegovim legurama i navode se uslovi ispitivanja i postignuta unapređenja.

Ključne reči: plazma nitriranje, nerđajući čelici, kalup za kovanje, legure titana, legure aluminijuma, korozija, habanje

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Ihebrodike Maurice Mejeha1*,  Kelechukwu Bierechi Okeoma1,  Uchechi Agoh1, Daniel Chukwuebuka Igweze1, Jasper Tamadu Obi1,2

1 Federal University of Technology, Materials Research Group, Department of Physics, Owerri, Owerri, Nigeria, 1,2 Isaac Jasper Boro College of Education, Department of Physics, Sagbama, Yenagoa, Nigeria

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203271M

Zastita Materijala 63 (3)
271 – 279 (2022)

 

The protective effect of magnetic fields on the corrosion of aluminium alloys in hydrochloric acid solutions

Abstract

The effect of applied magnetic fields on the corrosion of aluminium alloys AA3003 and AA8011 in hydrochloric acid solutions at room temperature has been investigated by using the gravimetric technique. The magnetic fields were generated from a locally made electromagnet with variable outputs. They were applied at right angles to the surfaces of the aluminium alloy samples when completely immersed in the test solutions. The corrosion rates of the aluminium alloys AA3003 and AA8011 in 0.5M HCl acid solutions were monitored at different applied magnetic fields. Results show that the corrosion rates of the aluminium alloy samples studied decrease with increase in the applied magnetic field. This implies that the presence of magnetic field inhibits the corrosion of the aluminium alloy AA3003 and AA8011 samples. With applied magnetic fields in the range of 254.3 – 1040.6 mG [0.0254 – 0.1041 mT], the protection efficiency of the magnetic field observed for AA3003 in 0.5M HCl acid solutions ranges from 19.3 – 94.1% while for aluminium alloy AA8011 in identical test solutions, the protection efficiency ranges from 11.5 – 78.0%. The protection mechanism is attributed partly to the phenomenon of transverse magnetoresistance and partly to effect of the magnetic fields on the mass transport pattern of constituent ions in the electrochemical system.

Keywords: Magnetic field, aluminium alloys, gravimetric technique, corrosion rate, protection efficiency, transverse magnetoresistance.

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ZAŠTITNO DEJSTVO MAGNETNOG POLJA NA KOROZIJU ALUMINIJUMSKIH LEGURA U RASTVORIMA HLOROVODONIČNE KISELINE

Izvod

Gravimetrijskom tehnikom ispitan je uticaj primenjenih magnetnih polja na koroziju legura aluminijuma AA3003 i AA8011 u rastvorima hlorovodonične kiseline na sobnoj temperaturi. Magnetno polje je generisano od lokalno napravljenog elektromagneta sa promenljivim izlazima. Naneti su pod pravim uglom na površine uzoraka legure aluminijuma kada su potpuno uronjeni u ispitne rastvore. Praćene su brzine korozije legura aluminijuma AA3003 i AA8011 u 0,5M rastvorima HCl kiselina pri različitim primenjenim magnetnim poljima. Rezultati pokazuju da se brzine korozije ispitivanih uzoraka legure aluminijuma smanjuju sa povećanjem primenjenog magnetnog polja. Ovo implicira da prisustvo magnetnog polja inhibira koroziju uzoraka legure aluminijuma AA3003 i AA8011. Sa primenjenim magnetnim poljima u opsegu od 254,3 – 1040,6 mG [0,0254 – 0,1041 mT], zaštitna efikasnost magnetnog polja primećena za AA3003 u 0,5M rastvorima HCl kiseline kreće se od 19,3 – 94,1% dok je za identičan rastvor aluminijuma AA80 allo1 test , efikasnost zaštite se kreće od 11,5 – 78,0%. Mehanizam zaštite se delom pripisuje fenomenu poprečne magnetootpornosti, a delom uticaju magnetnih polja na obrazac transporta mase konstitutivnih jona u elektrohemijskom sistemu.

Ključne reči: Magnetno polje, legure aluminijuma, gravimetrijska tehnika, brzina korozije, efikasnost zaštite, poprečna magnetootpornost.

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Dorothy Rajendran1*, Thankappan Sasilatha1, Susai Rajendran2,3, Senthil Kumaran Selvaraj4 , Caslav Lacnjevac5, Sivakumar Santhana Prabha6, Rajendran Joseph Rathish6

1AMET University, Department of EEE, Kanathur, East Coast Road, Chennai, India, 2St. Antony’s College of Arts and Sciences for Women Thamaraipady,Corrosion Research Centre, Department of Chemistry, Dindigul – 624005,Tamil Nadu, India, 3Pondicherry University, Puducherry, India. 4Vellore Institute of Technology (VIT), Department of Manufacturing Engineering, School of Mechanical Engineering-SMEC, Tamil Nadu, India. 5University of Belgrade, Faculty of Agriculture, Belgrade, Serbia, 6PSNA College of Engineering and Technology, , Dindigul, India.

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203280R

Zastita Materijala 63 (3)
280 – 290 (2022)

 

Application of machine learning in corrosion inhibition study

Abstract

Artificial intelligence is a branch of science concerned with teaching machines to think and act like humans. Machine learning is concerned with enabling computers to perform tasks without the need for explicit programming. Machine Learning enables computers to learn without the need for explicit programming. Machine Learning is a broad field that encompasses a wide range of machine learning operations such as clustering, classification, and the development of predictive models. Machine Learning (ML) and Deep Learning (DL) research is now finding a home in both industry and academia. Machine Learning technologies are increasingly being used in medical imaging. To detect tumours and other malignant growths in the human body. Deep Learning is making significant contributions to the advancement of industrial robotics. Machine learning algorithms are used in the self-driving car industry to guide the vehicle to its destination. Deep Learning and Machine Learning are also used in corrosion science and engineering. They are used to choose the inhibitor molecules from a large pool of available molecules.

Keywords: Artificial Intelligence, Machine learning, Deep learning, Neural Networks,Algorithms, The Input Layer, The Hidden Layer and The Output Layer.

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Primena mašinskog učenja u proučavanju inhibicije korozije

Izvod

Veštačka inteligencija je grana nauke koja se bavi učenjem mašina da misle i deluju kao ljudi. Mašinsko učenje se bavi omogućavanjem računarima da izvršavaju zadatke bez potrebe za eksplicitnim programiranjem. Mašinsko učenje omogućava računarima da uče bez potrebe za eksplicitnim programiranjem. Mašinsko učenje je široko polje koje obuhvata širok spektar operacija mašinskog učenja kao što su grupisanje, klasifikacija i razvoj prediktivnih modela. Istraživanje mašinskog učenja (ML) i dubokog učenja (DL) sada pronalazi dom i u industriji i u akademskim krugovima. Tehnologije mašinskog učenja se sve više koriste u medicinskom snimanju. Za otkrivanje tumora i drugih malignih izraslina u ljudskom telu. Duboko učenje daje značajan doprinos napretku industrijske robotike. Algoritmi mašinskog učenja se koriste u industriji automobila koji se samostalno voze da vode vozilo do odredišta. Duboko učenje i mašinsko učenje se, takođe, koriste u nauci o koroziji i inženjerstvu. Koriste se za odabir molekula inhibitora iz velikog skupa dostupnih molekula.

Ključne reči: veštačka inteligencija, mašinsko učenje, duboko učenje, neuronske mreže, algoritmi, ulazni sloj, skriveni sloj i izlazni sloj.

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Subrata Das*, Keerthana Shanmugaraja

Department of Fashion Technology, Bannari amman Institute of Technology, Sathyamangalam, Tamil Nadu 638401, India

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203291D

Zastita Materijala 63 (3)
291 – 299 (2022)

 

Application of artificial neural network in determining the fabric weave pattern

Abstract

The weave pattern (texture) of woven fabric is considered to be an important factor of the design and production of high-quality fabric. Traditionally, the recognition of woven fabric has a lot of challenges due to its manual visual inspection. The approaches based on early machine learning algorithms directly depend on handcrafted features, which are time-consuming and occurs more errors. Hence, an automated system is needed for classification of woven fabric to improve productivity. Along with the rapid development of computer vision, the automatic and efficient methods for woven fabric classification are desperately needed. The prediction of fabric weave pattern Fabric is done by acquiring the high-quality images of the fabric. Then the acquired images are subjected to weave classification algorithm. The output of the processed image is used as an input to the Artificial Neural Network (ANN) which uses back propagation algorithm to calculate the weighted factors and generates the desired classification of weave patterns as an output. In this review paper discussed about the study on the various neural network that are used for prediction of fabric weave pattern.

Keywords: Artificial Neural Network (ANN), Fabric pattern, fabric pattern prediction, Classification of fabric pattern, Back propagation algorithm.

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PRIMENA VEŠTAČKE NEURALNE MREŽE U ODREĐIVANJU OBRAZA TKANJA

Izvod

Uzorak tkanja (tekstura) tkanog materijala smatra se važnim faktorom dizajna i proizvodnje visokokvalitetnih tkanina. Tradicionalno, prepoznavanje tkanog materijala ima mnogo izazova zbog ručnog vizuelnog pregleda. Pristupi zasnovani na ranim algoritmima mašinskog učenja direktno zavise od ručno izrađenih funkcija, koje oduzimaju mnogo vremena i javljaju se više grešaka. Dakle, potreban je automatizovani sistem za klasifikaciju tkanog materijala da bi se poboljšala produktivnost. Zajedno sa brzim razvojem kompjuterskog vida, očajnički su potrebne automatske i efikasne metode za klasifikaciju tkanih tkanina. Predviđanje tkanja uzorka tkanine se vrši dobijanjem visokokvalitetnih slika tkanine. Zatim se dobijene slike podvrgavaju algoritmu za klasifikaciju tkanja. Izlaz obrađene slike se koristi kao ulaz u Veštačku neuronsku mrežu (ANN) koja koristi algoritam povratne propagacije da izračuna ponderisane faktore i generiše željenu klasifikaciju uzoraka tkanja kao izlaz. U ovom preglednom radu govori se o studiji o različitim neuronskim mrežama koje se koriste za predviđanje uzorka tkanine.

Ključne reči: Veštačka neuronska mreža (ANN), Dezen tkanine, predviđanje uzoraka tkanine, Klasifikacija uzoraka tkanine, Algoritam povratnog širenja.

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Vyacheslav Goryany1*, Olga Myronova2

1Düsseldorf, Germany, 2University of Duisburg-Essen, Institute for Technology of Metals, Duisburg, Germany

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203300G

Zastita Materijala 63 (3)
300 – 308 (2022)

 

Modern materials for cast rolls of hot strip mills

Abstract

The requirements for the work rolls for the various roll stands of hot strip mills are shown. The modern materials for cast rolls are analyzed and the operational performance of different types of rolls in different stands of the rolling mill is described. The trends in improvement of rolls performance were presented.

Keywords: cast rolls, microstructure, martensit, carbide, mechanical properties

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SAVREMENI MATERIJALI ZA LIVENE VALJKE U VALJAONICAMA ZA TOPLO VALJANJE LIMOVA

Izvod

Prikazani su zahtevi za radne valjke različitih stanova valjačkih pruga za toplo valjanje lima. Analizirani su savremeni materijali za livene valjke i opisane su operativne performanse različitih vrsta valjaka u različitim stanovima valjačkih pruga. Predstavljeni su trendovi u poboljšanju performansi valjaka.

Ključne reči: liveni valjci, mikrostruktura, martenzit, karbid, mehanička svojstva

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Leonid Dvorkin*, Vitalij Marchuk

National University of Water and Environmental Engineering, Rivne, Ukraine

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203309D

Zastita Materijala 63 (3)
309 – 317 (2022)

 

Dry mixes on the basis of reactive-powder concrete

Abstract

This article presents the results of experimental studies of mortars based on dry mixes using reactive-powder concrete (RPC). This type of concrete can serve not only as the structural material in the construction of buildings and structures, but also as a semi-finished product for obtaining dry building mixes for various purposes. Redispersed polymer powder as well as fly ash according to the results of the conducted research can be used as additional components for the preparation of various dry building mixes. For development of compositions of dry mixes used the statistical models received by means of mathematical planning of experiments.

Keywords: reactive-powder concrete, mortar, superplasticizer, composition, properties.

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SUVE MEŠAVINE NA OSNOVU REAKTIVNOG BETONA U PRAHU

Izvod

U ovom članku su prikazani rezultati eksperimentalnih ispitivanja maltera na bazi suvih mešavina sa reaktivnim praškastim betonom (RPC). Ova vrsta betona može poslužiti ne samo kao konstrukcijski materijal u izgradnji zgrada i objekata, već i kao poluproizvod za dobijanje suvih građevinskih mešavina za različite namene. Redispergovani polimerni prah kao i elektrofilterski pepeo prema rezultatima sprovedenih istraživanja mogu se koristiti kao dodatne komponente za pripremu različitih suvih građevinskih mešavina. Za izradu kompozicija suvih mešavina korišćeni su statistički modeli dobijeni pomoću matematičkog planiranja eksperimenata.

Ključne reči: reaktivni praškasti beton, malter, superplastifikator, sastav, svojstva.

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Ifeyinwa Calista Ekeke1,2,*, Steve Efe1, Felix Chigozie Nwadire3,4

1Morgan State University, Civil Engineering Department, Baltimore, Maryland, USA, 2Federal University of Technology, Chemical Engineering Department, Owerri, Imo State, Nigeria, 3Michael Okpara University, Chemistry Department, Umudike, Umuahia, Abia State, Nigeria,4Morgan State University, Chemistry Department, Baltimore, Maryland, USA.

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203318E

Zastita Materijala 63 (3)
318 – 340 (2022)

 

A review of amino acids used as corrosion inhibitors on iron metal/alloys in aggressive environments

Abstract

Research into the use of safe and environmentally friendly corrosion inhibitors can pave the way for an understanding of their inhibition mechanisms in metallic alloy materials. This review seeks to present and discuss the research work reported in the literature on the use of amino acids and their derivatives as corrosion inhibitors for iron and its alloys in different aggressive solutions. This non-toxic, biodegradable and relatively cheap corrosion inhibitor has shown to be efficient as an inhibitor for metals/alloys in acidic, alkaline and neutral solutions depending on experimental conditions. Electrochemical and surface techniques were among the most often used techniques to evaluate the corrosion inhibition efficiency of amino acids. Highest values of inhibition efficiency can be obtained in the presence of ions as I- and Br-. This review presents and discusses most of the contributions made in literature on the use of amino acids and their derivatives as corrosion inhibitors for iron and its alloys.

Keywords: corrosion inhibitor, iron, metal, alloy, amino acid, computational methods.

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PREGLED AMINOKISELINA KOJE SE KORISTE KAO INHIBITORI KOROZIJE NA METALU/LEGURAMA GVOŽĐA U AGRESIVNIM SREDINAMA

Izvod

Istraživanje upotrebe bezbednih i ekološki prihvatljivih inhibitora korozije može utrti put za razumevanje njihovih mehanizama inhibicije za materijale od metalnih legura. Ovaj pregled ima za cilj da predstavi i prodiskutuje istraživački rad objavljen u literaturi o upotrebi aminokiselina i njihovih derivata kao inhibitora korozije gvožđa i njegovih legura u različitim agresivnim rastvorima. Ovaj netoksičan, biorazgradiv i relativno jeftin inhibitor korozije pokazao se efikasnim kao inhibitor metala/legura u kiselim, alkalnim i neutralnim rastvorima u zavisnosti od eksperimentalnih uslova. Elektrohemijske i površinske tehnike bile su među najčešće korišćenim tehnikama za procenu efikasnosti inhibicije korozije aminokiselina. Najveće vrednosti efikasnosti inhibicije mogu se dobiti u prisustvu jona kao I- i Br-. Ovaj pregled predstavlja i razmatra većinu doprinosa u literaturi o upotrebi aminokiselina i njihovih derivata kao inhibitora korozije gvožđa i njegovih legura.

Ključne reči: inhibitor korozije, gvožđe, metal, legura, amino kiselina, računske metode

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Thangarajan Umamathi1*, Ramachandran Parimalam1, Venkatachalam Prathipa2,  Antony Josephine Vanitha1, Kalimuthu Muneeswari1,Babu Mahalakshmi1, Susai Rajendran3,4, Anitha Nilavan3

1Sri Meenakshi Government Arts College For Women (A), Department of Chemistry, Madurai , India, 2PSNA College of Engineering and Technology, Department of Chemistry, Dindigul, Tamilnadu, India, 3St. Antony’s College of Arts and Sciences For Women, Corrosion Research Centre, Department of Chemistry, Dindigul,Tamilnadu, India, 4Pondicherry University, Centre for Nanoscience and Technology, Puducherry, India

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203341U

Zastita Materijala 63 (3)
341 – 352 (2022)

 

Influence of urea and glucose on corrosion resistance of Gold 21K alloy in the presence of artificial sweat

Abstract

Corrosion resistance of Gold 21K alloy immersed in artificial sweat in the absence and presence of 100 ppm of urea and also 100 ppm of D-Glucose has been investigated by polarization study and AC impedance spectra. It is observed that Corrosion resistance of Gold 21K alloy immersed in artificial sweat in the presence of 100 ppm of urea / D-Glucose increases. Hence it is concluded that people wearing ornaments made of Gold 21K alloy need not worry about the excess of urea / D-Glucose in their sweat. When Gold 21K alloy is immersed in artificial sweat in the presence of 100 ppm of urea, Linear Polarisation Resistance value increases from 103389Ohmcm2 to 123437Ohmcm2; corrosion current decreases from 4.036 x10-7A/cm2 to 3.308 x10-7A/cm2; charge transfer resistance value increases from 10490 Ohmcm2 to 14070 Ohmcm2 ; impedance value increases from 4.253 to 4.324; double layer capacitance decreases from 4.862×10-10 F/cm2 to 3.625×10-10 F/cm2, and phase angle increases from 38.91 to 70.14. When Gold 21K alloy is immersed in artificial sweat in the presence of 100 ppm of D-Glucose, Linear Polarisation Resistance value increases from 103389Ohmcm2 to 4817257Ohmcm2; corrosion current decreases from 4.036 x10-7A/cm2 to 0.161×10-7A/cm2 ; charge transfer resistance increases from 10490Ohmcm2 to 33300Ohmcm2; impedance value increases from 4.253 to 4.977; double layer capacitance decreases from 4.862×10-10 F/cm2 to 1.5315×10-10 F/cm2, and phase angle increases from 38.91° to 79.74°.

Keywords: Corrosion resistance, Thermo active alloy, Gold 21K alloy, Artificial sweat, polarization study, AC impedance spectra.

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Uticaj uree i glukoze na otpornost legure zlata 21K na koroziju u prisustvu veštačkog znoja

Izvod

Otpornost na koroziju legure zlata 21K uronjene u veštački znoj u odsustvu i prisustvu 100 ppm uree i 100ppm D-glukoze je ispitana proučavanjem polarizacije i spektara impedanse naizmenične struje. Primećeno je da se povećava otpornost na koroziju legure zlata 21K uronjene u veštački znoj u prisustvu 100 ppm uree/D-glukoze. Otuda se zaključuje da ljudi koji nose ukrase od legure zlata 21K ne moraju da brinu o višku uree/D-glukoze u svom znoju. Kada se legura zlata 21K potopi u veštački znoj u prisustvu 100 ppm uree, vrednost otpora linearne polarizacije se povećava sa 103389 Ohmcm2 na 123437Ohmcm2; struja korozije opada sa 4,036 k10-7A/cm2 na 3,308 k10-7A/cm2; vrednost otpora prenosa naelektrisanja se povećava sa 10490 Ohmcm2 na 14070 Ohmcm2; vrednost impedanse se povećava sa 4,253 na 4,324; kapacitivnost dvostrukog sloja se smanjuje sa 4,862k10-10 F/cm2 na 3,625k10-10F/cm2, a fazni ugao se povećava sa 38,91° na 70,14°. Kada se legura zlata 21K potopi u veštački znoj u prisustvu 100ppm D-glukoze, vrednost otpora linearne polarizacije se povećava sa 103389 Ohmcm2 na 4817257Ohmcm2; struja korozije se smanjuje sa 4,036 k10-7A/cm2 na 0,161k10-7A/cm2; otpor prenosa naelektrisanja se povećava sa 10490 Ohmcm2 na 33300 Ohmcm2; vrednost impedanse se povećava sa 4,253 na 4,977; kapacitivnost dvoslojnog sloja se smanjuje sa 4,862k10-10 F/cm2 na 1,5315k10-10 F/cm2, a fazni ugao se povećava sa 38,91° na 79,74.

Ključne reči: otpornost na koroziju, termoaktivna legura, legura zlata 21K, veštački znoj, studija polarizacije, spektri impedanse naizmenične struje.

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Karunaivel Kavipriya1*, Maria Lurdu Lavanya2, Kuppusamy Bhuvaneswari2, Veerapandian Velkannan3, Nilavan Anitha2Susai Rajendran2,4, Caslav Lacnjevac5

1PSNA College of Engineering and Technology, Department of Chemistry, (Affiliated to Anna University, Chennai), Dindigul, India, 2St. Antony’s College of Arts and Sciences for Women, Department of Chemistry, Corrosion Research Centre, Dindigul-624005 (Affiliated to Mother Teresa Women’s University, Kodaikanal, India), 3Thiagarajar College of Engineering (Affiliated to Anna University, Chennai), Department of Chemistry, Thiruparankundram, Madurai, Tamil Nadu, India, 4Pondicherry University, Centre for Nanoscience and Technology, Puducherry, India, 5University of Belgrade, Faculty of Agriculture, Belgrade, Serbia.

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203353K

Zastita Materijala 63 (3)
353 – 362 (2022)

 

Influence of a paint coating on the corrosion of hull plates made of mild steel in natural seawater

Abstract

The corrosion resistance of mild steel (used to make hull plates in ship technology) in seawater before paint coating (Nippon paint, weatherbond advance) and after paint coating has been measured by electrochemical studies such as Polarisation study and AC impedance spectra. It is observed that after paint coating, the corrosion resistance of mild steel hull plates increases. Polarization study reveals that after paint coating, the linear polarization resistance increases and corrosion current decreases. AC impedance spectra reveal that in the presence of paint coating charge transfer resistance value increases, impedance value increases, phase angle increases and double layer capacitance value decreases.

Keywords: paint coating, corrosion inhibition, hull plates, mild steel, natural seawater, electrochemical studies

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Uticaj premaza na koroziju ploča trupa od mekog čelika u prirodnoj morskoj vodi

Izvod

Otpornost na koroziju mekog čelika (koji se koristi za izradu ploča trupa u brodskoj industriji) u morskoj vodi pre nanošenja boje (Nippon boja, vremenska veza unapred) i posle premaza boje je merena elektrohemijskim studijama kao što su studija polarizacije i spektri impedanse naizmenične struje. Primećeno je da se nakon nanošenja boje povećava otpornost na koroziju ploča trupa od mekog čelika. Studija polarizacije otkriva da nakon nanošenja boje, otpor linearne polarizacije raste a struja korozije opada. Spektri impedance naizmenične struje otkrivaju da se u prisustvu bojenog premaza vrednost otpora prenosa naelektrisanja povećava, vrednost impedanse povećava, fazni ugao raste i vrednost dvoslojne kapacitivnosti opada.

Ključne reči: premaz boje, inhibicija korozije, ploče trupa, meki čelik, prirodna morska voda, elektrohemijske studije

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Indrit Vozga*, Vladimir Kasemi

Polytechnic University of Tirana, Mechanical Engineering Faculty, Production and Management Department, Materials Section, Tirana, Albania

Scientific controversy
ISSN 0351-9465, E-ISSN 2466-2585
https://doi.org/10.5937/zasmat2203363V

Zastita Materijala 63 (3)
363 – 368 (2022)

 

Theoretical experimental aspects of composition with polymeric matrix reinforced with polymer particles

Abstract

The development of composite materials and related design and production methods is one of the most important advances in the history of materials. They can be accurately modeled to respond to the requirements of the most specific applications. Many composites show, in addition to high mechanical properties, also high resistance to corrosion at high temperatures, to oxidation and wear. These unique features give design possibilities that are not achieved with any of the traditional monolithic materials. Many technological processes of composites are best suited for the production of large and complex structures, which has allowed their compaction and realization in the form of “one body”, thus reducing production costs. The case of the composite with polymeric matrix reinforced with polymer particles is also interesting. PS and HDPE are two of the most used plastics in the world with a production scale of billions of tons. Less than 10% of this production is recycled. One use for recycled plastics, especially HDPE, is to melt into profiles that resemble beams, hence the term plastic beams. These products are used as building materials in many applications. One drawback of some plastic beam products is their tendency to slip.

Keywords: composite materials, polymeric matrix, mechanical properties, PS and HDPE, plastic beams, building materials

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TEORIJSKO EKSPERIMENTALNI ASPEKTI KOMPOZICIJE SA POLIMERNOM MATRICOM OJAČANOM POLIMERNIM ČESTICIMA

Izvod

Razvoj kompozitnih materijala i srodnih metoda projektovanja i proizvodnje jedan je od najvažnijih napredaka u istoriji materijala. Mogu se precizno modelovati da odgovore na zahteve najspecifičnijih aplikacija. Mnogi kompoziti pokazuju, pored visokih mehaničkih svojstava, i visoku otpornost na koroziju na visokim temperaturama, na oksidaciju i habanje. Ove jedinstvene karakteristike daju mogućnosti dizajna koje se ne postižu ni sa jednim od tradicionalnih monolitnih materijala. Mnogi tehnološki procesi kompozita su najpogodniji za proizvodnju velikih i složenih konstrukcija, što je omogućilo njihovo zbijanje i realizaciju u obliku „jednog tela“, čime se smanjuju troškovi proizvodnje.

Interesantan je i slučaj kompozita sa polimernom matricom ojačanom polimernim česticama. PS i HDPE su dve najkorišćenije plastike na svetu sa skalom proizvodnje od milijardi tona. Manje od 10% ove proizvodnje se reciklira. Jedna upotreba za recikliranu plastiku, posebno HDPE, je da se stapa u profile koji podsećaju na grede, otuda i termin plastične grede. Ovi proizvodi se koriste kao građevinski materijal u mnogim aplikacijama. Nedostatak nekih proizvoda od plastičnih greda je njihova sklonost klizanju.

Ključne reči: kompozitni materijali, polimerna matrica, mehanička svojstva, PS i HDPE, plastične grede, građevinski materijali.

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