Croatian Digital Thesis Repository
Not a member yet
259189 research outputs found
Sort by
Corrosion inhibition of titanium by propolis in simulated oral cavity conditions : diploma thesis
No full textTitanij (Ti) je zbog svoje visoke otpornosti na koroziju, izvanredne biokompatibilnosti, mogućnosti repasivacije i odgovarajućih mehaničkih svojstava postao standardni materijal za izradu dentalnih implantata. Korozijska otpornost ovog materijala povezana je s prisutnošću zaštitnog oksidnog sloja na površini. Međutim, usna šupljina predstavlja složenu sredinu koja može negativno utjecati na korozijsku otpornost, dugotrajnost i integritet titanijskih implantata. Jedna od često primjenjivanih metoda zaštite metala od korozije je zaštita metala inhibitorima korozije. U ovom radu istraživan je utjecaj etanolnog ekstrakta propolisa na korozijsko ponašanje titanija u simuliranim uvjetima usne šupljine pri različitim temperaturama. Istraživanja su provedena elektrokemijskim metodama (metoda mjerenja potencijala otvorenog kruga, metoda linearne polarizacije i potenciodinamička polarizacijska metoda). Nakon slijeda elektrokemijskih mjerenja površinski slojevi Ti analizirani su optičkim mikroskopom, a dodatna analiza elektrolitnih otopina i površinskih slojeva Ti provedena je infracrvenom spektroskopijom s Fourierovom transformacijom tehnikom univerzalne prigušene totalne refleksije (FTIR-UATR). Dobiveni rezultati pokazuju kako je etanolni ekstrakt propolisa mješoviti inhibitor korozije Ti u simuliranim uvjetima usne šupljine. Najveća inhibitorska djelotvornost 78 % postignuta je pri 36 °C, a povećanjem temperature inhibitorska djelotvornost se smanjuje. Izračunate energije aktivacije i termodinamički aktivacijski parametri ukazuju na to da se inhibicija korozije Ti etanolnim ekstraktom propolisa odvija fizisorpcijom, a proces adsorpcije je endoterman. Metodom FTIR-UATR u slojevima na površini uzoraka Ti identificirane su funkcionalne skupine prisutne u propolisu.Titanium (Ti) has become the standard material for dental implants due to its high corrosion resistance, excellent biocompatibility, repassivation ability, and suitable mechanical properties. The corrosion resistance of this material is related to the presence of a protective oxide layer on its surface. However, the oral cavity is a complex environment that can adversely affect titanium implants' corrosion resistance, longevity and integrity. One of the most commonly applied methods for protecting metals from corrosion is the use of corrosion inhibitors. In this study, the effect of ethanolic propolis extract on the corrosion behavior of titanium in simulated oral cavity conditions at different temperatures was investigated. The research was conducted using electrochemical methods (open circuit potential measurement method, linear polarization, and potentiodynamic polarization method). Following a sequence of electrochemical tests, an optical microscope was used to analyze the Ti surface layers. After that, the electrolyte solutions and the Ti surface layers were further examined using Fourier transform infrared spectroscopy employing universal attenuated total reflectance (FTIR-UATR). The results indicated that an ethanolic propolis extract acts as a mixed-type corrosion inhibitor for Ti under simulated conditions in the oral cavity. The maximum inhibitory efficiency of 78 % was achieved at 36 °C; the inhibitory efficiency decreases with increasing temperature. The determined activation energies and thermodynamic activation parameters show that an ethanolic propolis extract inhibits the corrosion of Ti by physisorption with an endothermic adsorption process. The functional groups present in the propolis were identified in the layers on the surface of the Ti samples using the FTIR-UATR method
Synthesis and characterization of new derivatives of tetrahydropyrrolo[3,4-b]indole with propargyl and tert-butyl ester groups as precursors of hybrid molecules with potential antimalarial activity
No full textMalarija je infektivna bolest tropskih i subtropskih krajeva koja svake godine bilježi porast mortaliteta, a nemogućnost
kontrole širenja bolesti predstavlja veliki izazov. Ovaj rad obuhvaća sintezu i karakterizaciju novih derivata
tetrahidropirolo[3,4-b]indola s propargilnom i tert-butilnom esterskom skupinom, kao prekursora hibridnih molekula s
potencijalnim antimalarijskim djelovanjem. Izabrani izocijanidni derivati dobiveni su iz odgovarajućih aminokiselina.
Propargilni esteri DL-alanina i L-fenilalanina (8, 13) pripravljeni su u 3 koraka, dok je tert-butilni ester DL-alanina (3)
pripravljen u jednom sintetskom koraku. Potom je amino-skupina pripravljenih estera (3, 8, 13) prevedena u
formamidnu, a u posljednjem koraku formamidi su prevedeni u odgovarajuće izocijanidne derivate (5, 10, 15). Dobiveni
spojevi (16, 17, 18) korišteni su u reakciji dearomatizacije N-tosil-3-nitroindola (2) koji je prethodno pripravljen iz
indola u 2 koraka. Zbog nestabilnosti spojeva dobivenih dearomatizacijom provedena je in situ redukcija uz NaBH3CN.
U daljnjim istraživanjima, koja prelaze okvire ovog rada, click-reakcijom propargilne skupine pripravljenog spoja i
molekule koja sadrži funkcionalnu skupinu azid sintetizirat će se novi hibridni spojevi potencijalnog anitmalarijskog
djelovanja.Malaria is an infectious disease found in tropical and subtropical regions, which records an annual increase in mortality,
and the inability to control the spread of the disease presents a major challenge. This paper covers the synthesis and
characterization of new derivatives of tetrahydropyrrolo[3,4-b]indole with propargyl and tert-butyl ester groups as
precursors of hybrid molecules with potential antimalarial activity. The selected isocyanide derivatives were obtained
from the corresponding amino acids. Propargyl esters of DL-alanine and L-phenylalanine (8, 13) were prepared in three
steps, while the tert-butyl ester of DL-alanine (3) was synthesized in a single synthetic step. The amino group of the
prepared esters (3, 8, 13) was then converted to a formamide group, and in the final step, the formamides were converted
into the corresponding isocyanide derivatives (5, 10, 15). The obtained compounds (16, 17, 18) were used in the
dearomatization reaction of N-tosyl-3-nitroindole (2), which was previously synthesized from indole in two steps. Due
to the instability of the compounds obtained through dearomatization, in situ reduction was performed using NaBH3CN.
In further research, beyond the scope of this work, new hybrid compounds with potential antimalarial activity will be
synthesized by performing a click reaction between the propargyl group of the prepared compound and a molecule
containing an azide functional group
Metabolomic study: identification of hexadecanal as a potential biomarker for preeclampsia : diploma thesis
No full textU ovom diplomskom radu provedena je ne-ciljana metabolomička analiza hlapljivih organskih metabolita u uzorcima urina trudnica s ciljem pronalaska i identifikacije potencijalnih biomarkera preeklampsije – ozbiljnog metaboličkog poremećaja koji se javlja tijekom trudnoće. Ukupno je analiziran 91 uzorak urina, od čega je 45 uzoraka pripadalo trudnicama s dijagnosticiranom preeklampsijom, a ostalih 46 uzoraka zdravih trudnica služilo je kao kontrolna skupina. Kemijska analiza temeljena je na mikroekstrakciji vršnih para na krutoj fazi u kombinaciji s vezanim sustavom plinske kromatografije i spektrometrije masa (HS-SPME/GC-MS), nakon čega je uslijedila obrada podataka i statistička analiza kako bi se identificirali statistički značajni metaboliti. Provedba ove opsežne metabolomičke studije rezultirala je identifikacijom ukupno 29 hlapljivih metabolita u obje ispitivane skupine uzoraka, pri čemu se heksadekanal istaknuo kao statistički najznačajniji spoj povezan s preeklampsijom. Analiza biomarkera pokazala je obećavajući dijagnostički potencijal heksadekanala, dok je analiza obogaćenja istaknula njegovu povezanost sa metabolizmom sfingolipida. Stoga ova studija pozicionira heksadekanal kao potencijalni neinvazivni biomarker preeklampsije, pružajući novi uvid u metaboličke poremećaje koji stoje u pozadini patofiziologije ovog ozbiljnog zdravstvenog stanja.In this thesis, an untargeted metabolomics analysis of volatile organic metabolites in urine samples from pregnant women was conducted. The aim of it was identifying potential biomarkers for preeclampsia – a serious metabolic disorder that occurs during pregnancy. A total of 91 urine samples were analyzed, 45 of which belonged to pregnant women diagnosed with preeclampsia, while the remaining 46 samples from healthy pregnant women served as the control group. The chemical analysis was based on solid-phase microextraction of headspace vapor, combined with gas chromatography-mass spectrometry (HS- SPME/GC-MS), followed by data processing and statistical analysis to identify statistically significant metabolites. This comprehensive metabolomics study resulted in the identification of 29 volatile organic metabolites across both groups, with hexadecanal standing out as the most statistically significant compound associated with preeclampsia. Biomarker analysis demonstrated the promising diagnostic potential of hexadecanal, while enrichment analysis highlighted its connection to sphingolipid metabolism. Therefore, this study positions hexadecanal as a potential non-invasive biomarker for preeclampsia, providing fresh insights into the metabolic disturbances underlying the pathophysiology of this serious health condition
Application of electrospun membranes in "lung-on-a-chip" models for simulating the alveolar barrier
No full textRazvoj funkcionalnog "lung-on-a-chip" modela, koji na vjerodostojan način oponaša kompleksnu strukturu i funkciju alveolarno-kapilarne barijere, središnja je tema ovoga rada. Inspiriran fiziologijom ljudskih pluća, model je osmišljen kao multifunkcionalna platforma za istraživanje prijenosa tvari kroz plućno tkivo, ispitivanje djelovanja inhalacijskih pripravaka te evaluaciju toksičnosti aerosola i drugih inhalacijskih agensa. Ključni korak u njegovoj izradi bila je primjena metode elektroispredanja za dobivanje tankih, biokompatibilnih membrana od polikaprolaktona, pri čemu je posebna pažnja posvećena optimizaciji uvjeta izrade kako bi se što bolje reproducirale mehaničke i morfološke karakteristike plućnog tkiva. Osim toga, u sustav su integrirani hidrogelovi na bazi natrijeva alginata, koji omogućuju kontroliranu difuziju i upotpunjuju model pluća. Cilj istraživanja je izraditi dinamički model koji „diše“, odnosno simulira mehaničke sile disanja, čime se dobiva realistični prikaz respiratorne funkcije u in vitro uvjetima. Takav sustav otvara mogućnosti za unapređenje inhalacijskih terapija, provedbu toksikoloških ispitivanja te razvoj alternativnih metoda za analizu plućnih funkcija bez upotrebe životinjskih modela. Model predstavlja značajan napredak u području biomedicine i kemijskog inženjerstva, jer omogućuje ubrzanje procesa razvoja lijekova i terapija. Njegova primjena omogućuje bržu i etički prihvatljiviju evaluaciju novih terapija, osobito u područjima pulmologije i farmacije, čime postaje vrijedan alat doprinoseći razvoju sigurnijih i učinkovitijih terapijskih rješenja za respiratorne bolesti.The development of a functional lung-on-a-chip model that accurately mimics the complex structure and function of the alveolar-capillary barrier is the central focus of this work. Inspired by the physiology of the human lung, the model is designed as a multifunctional platform for studying substance transport across pulmonary tissue, evaluating the effects of inhaled formulations, and assessing the toxicity of aerosols and other inhalable agents. A key step in the fabrication of the model involved the application of electrospinning to produce thin, biocompatible membranes made of poly(ε-caprolactone), with particular attention given to optimizing fabrication conditions to best replicate the mechanical and morphological properties of lung tissue. Additionally, the system incorporates sodium alginate-based hydrogels, which enable controlled diffusion and complement the lung model. The aim of the research is to develop a dynamic, “breathing” model that simulates the mechanical forces of respiration, thereby providing a realistic representation of respiratory function under in vitro conditions. Such a system offers new opportunities for improving inhalation therapies, conducting toxicological testing, and developing alternative methods for analyzing lung function without the use of animal models. This model represents a significant advancement in the fields of biomedicine and chemical engineering, as it accelerates the process of drug and therapy development. Its application enables faster and more ethically acceptable evaluation of new therapies, particularly in the fields of pulmonology and pharmaceutical sciences, making it a valuable tool in the pursuit of safer and more effective therapeutic solutions for respiratory diseases
Quantum memory in warm rubidium atomic vapor
No full textRazvoj kvantnih tehnologija−osobito kvantne komunikacije, računala i senzora ukazao je na potrebu za kontroliranim pohranjivanjem kvantne informacije radi distribucije isprepletenih stanja i sinkronizacije kvantnih mreža. To je potaknulo razvoj optičkih kvantnih memorija koje omogućuju pohranu kvantnih stanja svjetlosti i njihovo otpuštanje na zahtjev. Cilj ovog diplomskog rada je razvoj, karakterizacija i optimizacija ključnih komponenti za realizaciju kvantne memorije u toplim parama atoma rubidija, temeljene na efektu elektromagnetski inducirane transparencije (EIT). Rad započinje osvrtom u kojem se pomoću optičkih Blochovih jednadžbi opisuje kako pojava elektromagnetski inducirane transparencije omogućuje pohranjivanje informacije u atomski medij te se identificiraju parametri ključni za rad i
optimizaciju performansi kvantne memorije. U prvom dijelu eksperimentalnog rada, korištenjem klasične svjetlosti određeni su optimalni uvjeti za rad optičke memorije s obzirom na vrijeme i učinkovitost pohrane svjetlosti. Utvrđeno je da se najviša efikasnost pohrane fotona postiže u nerezonantnoj EIT shemi, koja je stoga i detaljno istražena. U završnom dijelu diplomskog rada osmišljena je i dizajnirana nadogradnja postojećeg eksperimentalnog postava s ciljem prelaska na kvantne memorije, a testirane su i osnovne komponente sustava nužne za rad s pojedinačnim fotonima.The development of quantum technologies, particularly quantum communication, computing, and sensing has highlighted the need for controlled storage of quantum information for the distribution of entangled states and synchronization of quantum networks. This has driven the development of optical quantum memories, which enable the storage of quantum states of light and their on-demand retrieval. The aim of this thesis is the development, characterization, and optimization of key components for the implementation of a quantum memory in warm rubidium vapor, based on the effect of electromagnetically induced transparency (EIT). The work begins with a theoretical overview using the optical Bloch equations to describe how the phenomenon of electromagnetically induced transparency enables the storage of information in an atomic medium, and it identifies the parameters critical for the operation and optimization of the quantum memory. In the first part of the experimental thesis, optimal conditions for the operation of the optical memory were determined with respect to the storage time and efficiency using classical light. It was found that the highest photon storage efficiency is achieved in an off-resonant EIT scheme, which was therefore investigated in detail. In the final part of the thesis, an upgrade to the existing experimental setup was designed and implemented with the goal of transitioning to quantum memory operation. Basic components necessary for working with single photons were also tested
Biocatalytical raspberry ketone production from renewable resources
No full textOvaj rad istražuje biokatalitičku proizvodnju ketona maline iz rododendrol glikozida, sekundarnih metabolita koji se mogu pronaći u unutarnjoj kori breze (obnovljivi izvor), primjenom višenzimatskog procesa. Cilj je bio razviti održiv i ekološki prihvatljiv proces sinteze ketona maline korištenjem enzima β-glukozidaze, alkohol dehidrogenaze, ketoreduktaze i smjese enzima rapidaza. Osim usporedbe simultanih i sekvencijalnih reakcijskih pristupa i pronalaženja optimalnog načina reakcije, provedena je studija stabilnosti dviju alkohol dehidrogenaza (S-selektivne i R-selektivne). Eksperimentalni dio uključivao je praćenje koncentracija supstrata, međuprodukata i produkata putem HPLC analize, kao i operativnu stabilnost enzima korištenjem spektrofotometrijskih metoda. Dodatno je proveden utjecaj koncentracije svake komponente u sustavu na stabilnost alkohol dehidrogenaze (ADH). Sinteza ketona malineprovedena je pod različitim temperaturama i pH vrijednostima, kako bi se optimirao proces. Ova vrsta sinteze predstavlja obećavajuću alternativu tradicionalnim metodama kemijske sinteze, s naglaskom na održivost, selektivnost i smanjenje štetnih nusprodukata.This study explores the biocatalytic production of raspberry ketone from rhododendrol glycosides, secondary metabolites that can be found in inner birch bark (renewable source), applying multi-enzymatic process. The objective was to develop a sustainable and environmentally friendly synthesis process for raspberry ketone by employing enzymes: β- glucosidase, alcohol dehydrogenases, ketoreductases, and the enzyme mixture Rapidase. Besides comparison of simultaneous and sequential reaction approaches and finding optimal reaction mode, stability study of two alcohol dehydrogenases (S-selective and R-selective) was performed. The experimental part included the monitoring of the concentrations of substrates, intermediates, and products via HPLC analysis, as well as the operational stability of enzymes using spectrophotometric methods. Additionally, the influence of concentration of each component in the system on the alcohol dehydrogenases (ADH) stability was done. The synthesis of raspberry ketone were carried out at various conditions, including different temperatures and pH, to optimize the process. This type of synthesis presents a promising alternative to traditional chemical synthesis methods, emphasizing sustainability, selectivity, and the reduction of harmful by-products
Improvement of technical sales support in engineering companies
No full textTema ovog rada je unaprjeđenje tehničke podrške prodaji u inženjerskim poduzećima. U prvom dijelu rada prikazana je evolucija prodajnih procesa te su opisani koraci prilikom predstavljanja novog proizvoda. Nakon upoznavanja procesa prodaje, predstavljeno je zanimanje inženjera prodaje, opisana je njihova uloga u poduzeću te je prikazan utjecaj prodajnih inženjera na efikasnost prodajnih predstavnika. U nastavku rada definirani su digitalni alati koji se koriste u prodaji dok je u glavnom dijelu rada, na realnom primjeru, prikazana uloga inženjera prilikom tehničke podrške prodaji, opisan je proces analize žičane forme u svrhu povećanja udjela vlastitih komponenti u navedenoj žičanoj formi te su prikazani udjeli pojedinih dobavljača prije i nakon provedene analize. U praktičnom dijelu rada također je prikazano poboljšanje procesa korištenjem automatizirane baze podataka koja olakšava rad inženjerima prilikom tehničke podrške prodaji.The topic of this paper thesis is improvement of technical sales support in engineering companies. After introduction, evolution of sales processes is explained at the beginning. After that historical development of sales, process of introducing new product is described. Sales engineers and their impact on the salesperson efficiency are being introduced in third chapter and in the fourth chapter sales technologies are being presented. Afterwards, analysis of wire harness is explained in order to increase share of companies components. In the end of this paper, the improvement of technical sales process is described on the example of using automated database which removes most of the manual work from the wire harness analysis. Finally, conclusions and learnings are shared
Inhibition of human cholinesterases by O-alkyloximes
No full textAcetilkolinesteraza (AChE) i butirilkolinesteraza (BChE) su enzimi koji kataliziraju hidrolizu acetilkolina i njihova inhibicija jedna je od glavnih strategija u liječenju Alzheimerove bolesti (AB). No, budući da je AB multifaktorijalna bolest, noviji pristup liječenju je razvoj lijekova s višestrukim učinkom koji bi istovremeno djelovali na više mogućih uzročnika bolesti. U sklopu ovog diplomskog rada testirano je 20 O-alkiloksima kao inhibitora ljudskih AChE i BChE, a za nekolicinu spojeva procijenjena je sposobnost vezanja u periferno mjesto AChE i sposobnost inhibicije β-amiloidne samoagregacije. Svi ispitani spojevi reverzibilno su inhibirali obje kolinesteraze u mikromolarnom području, s konstantama inhibicije Ki u rasponu 0,30 – 360 μmol dm–3. Najjačim inhibitorom AChE pokazao se spoj 20 (Ki = 6 μmol dm–3), dok je BChE najjače inhibirao spoj 15 (Ki = 0,30 μmol dm–3). Gotovo svi ispitivani O-alkiloksimi pokazali su se selektivnim inhibitorima BChE u odnosu na AChE. Sposobnost vezanja u periferno mjesto AChE i moguće sprječavanje nastajanja neurotoksičnog kompleksa AChE-β-amiloid pokazali su spojevi 2, 18, 19 i 20. Kao inhibitori β-amiloidne samoagregacije istaknuli su se spojevi 18 i 20. Za sve spojeve je in silico procijenjena sposobnost prolaska kroz krvno-moždanu barijeru te je pokazano da bi mogli prijeći krvno-moždanu barijeru pasivnim transportom.Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are enzymes that catalyze the hydrolysis of acetylcholine, and their inhibition is one of the main strategies in the treatment of Alzheimer's disease (AD). But, AD is a multifactorial disease so a new approach to treatment is development of multi-target directed ligands that would simultaneously act on several possible causes of the disease. As part of this thesis, 20 O-alkyloximes were tested as inhibitors of human AChE and BChE, and some of them were also tested for ability to bind to the peripheral site of AChE and to inhibit β-amyloid self-aggregation. All tested compounds reversibly inhibited both cholinesterases with inhibition constants Ki in the range of 0,30 – 360 μmol dm–3. The most potent AChE inhibitor was compound 20 (Ki = 6 μmol dm–3), while that of BChE was compound 15 (Ki = 0,30 μmol dm–3). Tested O-alkyloximes were generally more selective inhibitors of BChE than of AChE. Compounds 2, 18, 19 and 20 showed the ability to bind to the peripheral site of AChE and possible attenaution of formation of the neurotoxic AChE-β-amyloid complex. Compounds 18 and 20 proved to inhibit β-amyloid self-aggregation. All compounds were evaluated in silico for ability to pass the blood-brain barrier and all of them should be able to pass the blood-brain barrier by passive transport
Gamma-radiolytic degradation of loratadine in water
No full textLoratadin je antihistaminik koji se zbog česte upotrebe može pojaviti u otpadnim vodama što predstavlja rastući rizik za okoliš. Primjena ionizirajućeg zračenja pokazala se kao dobra alternativna metoda pročišćavanja otpadnih voda. U ovom radu provedena je razgradnja loratadina primjenom gama-zračenja. Utjecaj brzine i doze zračenja, te prisutnost različitih anorganskih soli i hvatača radikala na učinkovitost razgradnje određena je tekućinskom kromatografijom visoke djelotvornosti. Razgradni produkti analizirani su vezanim sustavom tekućinske kromatografije ultravisoke djelotvornosti i spektrometrije masa visokog razlučivanja. Na temelju MS i MS/MS spektara predložene su njihove strukture i razgradni put loratadina.Loratadine is an antihistamine which, because of the frequent use, can be found in wastewater, presenting a growing environmental risk. Ionizing radiation was found to be an effective alternative wastewater purification method. In this work degradation of loratadine by gamma irradiation was performed. The efficiency of degradation at different radiation rates and doses, in the presence of various inorganic salts and radical scavengers was investigated by high performance liquid chromatography. The degradation products were analysed by ultra high-performance liquid chromatography coupled to high-resolution mass spectrometry. Structures of degradants and degradation pathway of loratadine were proposed based on obtained results
Comparison of AC MIG and MIG-P processes in welding of 5083 and 6082 aluminium alloys
No full textTema završnog rada obrađena je teorijski i eksperimentalno. U teorijskom dijelu naglasak je na MIG postupku zavarivanja te dvjema varijacijama postupka na temelju struje i vrste prijenosa metala, a to su AC MIG te DC MIG-P zavarivanje. Objašnjene su glavne značajke svakog te prednosti i mane svakog od njih. Također, kod aluminijskih legura EN AW 5083-H321 i EN AW 6082-T6 obrađen je problem njihove zavarljivosti te dodatnog materijala i plinova koji se koriste tijekom zavarivanja ovih legura. Naposljetku, sukladno zahtjevima norme HRN EN ISO 15614-2, opisan je fenomen pada čvrstoće u području zavarenog spoja. Eksperimentalni dio rada proveden je ispitivanjem tvrdoće metodom Vickers, opterećenjem HV5 na navedenim aluminijskim legurama te je kvantificirana širina područja zone utjecaja topline. Naposljetku, određen je relativni pad čvrstoće u području zavarenog spoja te je predložena primjena AC MIG postupka u izradi aluminijskih zavarenih konstrukcija.The topic of the final paper was treated theoretically and experimentally. In the theoretical
part, the emphasis is on the MIG welding process and two variations of the process based on
current and metal transfer processes that arose from it, AC MIG and DC-MIG-P welding. The
main features of each and the advantages and disadvantages of each are explained. Also, in the
case of aluminum alloys EN AW 5083-H321 and EN AW 6082-T6, the problem of their
weldability and the additional material and gases used during welding of these alloys was
addressed. Finally, in accordance with the requirements of the HRN EN ISO 15614-2 standard,
the phenomenon of strength drop in the area of the welded joint is described.
The experimental part of the work was carried out by testing the hardness using the Vickers
method, with the HV5 load on the mentioned aluminum alloys, and the width of the area of the
heat-affected zone was quantified. Finally, the relative decrease in strength in the area of the
welded joint was determined, and the application of the AC MIG process in the production of
aluminum welded structures was proposed