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Application of digital twins in corrosion
No full textU zadnje vrijeme sve se više istražuju mogućnosti primjene digitalnih blizanaca u koroziji kao i njihova primjena u drugim industrijama. Digitalni blizanci su virtualni prikaz stvarnih fizičkih sustava koji nastaju pomoću podataka koje prikupljaju senzori, kamere i drugi izvori informacija o sustavu. Oni pružaju do sada neviđenu razinu kontrole nad fizičkim uređajima i pomažu upravljati složenim sustavima. Korozija je sveprisutan problem koji ima veliku važnost u širokom rasponu industrijskih primjena i proizvoda, stoga je isplativo ulagati i proučavati nove tehnologije poput digitalnih blizanaca s kojima bi se postigla bolja kontrola procesa korozije. U ovom radu dan je pregled najnovijih primjena digitalnih blizanaca u koroziji. Detaljnije je opisan razvoj digitalnog blizanca za prediktivno održavanje zaštitnih premaza na vjetroelektranama. Prikazana je mogućnost integracije podataka dobivenih pomoću različitih senzora, kao i matematički modeli održavanja. Ostali kraće opisani primjeri uključuju primjenu digitalnih blizanaca za održavanje podvodnih i ukopanih cjevovoda i betonskih mostova. Navedeni primjeri ilustriraju mogućnosti i upućuju na prednosti primjene digitalnih blizanaca u korozijskim sustavima.Recently, the possibilities of using digital twins in corrosion and their application in other industries have been increasingly explored. Digital twins are virtual representations of real physical systems created using data collected from sensors, cameras and other sources of information about the system. They provide an unprecedented level of control over physical devices and help manage complex systems. Corrosion is a pervasive problem that is of great importance in a wide range of industrial applications and products. Therefore, it is worth investing in and investigating new technologies such as digital twins to achieve better control of the corrosion process. This paper provides an overview of the latest applications of digital twins in corrosion. The development of digital twins for predictive maintenance of protective coatings on wind farms is described in more detail. The possibility of integrating data obtained with different sensors and mathematical maintenance models are presented. Other briefly described examples include the application of digital twins for the maintenance of underwater and underground pipelines as well as concrete bridges. The above examples illustrate the possibilities and show the advantages of using digital twins in corrosion systems
Synthesis of copper(II) oxide nanorods
No full textU ovom radu pripravljene su i karakterizirane nanočestice bakrova(II) oksida. Sinteza nanočesticca bakrova(II) oksida provedena je sonokemijskom metodom. Kako bi se dobio uvid u sastav i svojstva dobivenog uzorka, uzorak je podvrgnut brojnim analizama. Kristalna struktura i veličina kristalita određene su rendgenskom difrakcijskom analizom, uzorak je analiziran i infracrvenom spektroskopijom s Fourierovom transformacijom, termogravimetrijskom analizom, pretražnom elektronskom mikroskopijom, energijski disperzivnom rendgenskom spektroskopijom, a veličina i oblik čestica istraženi su mikroskopom atomskih sila. Potvrđeno je postojanje jedne faze u uzorku, bakrova(II) oksida, s kristalitima veličine do 20 nm. TGA analiza pokazala da je u uzorku prisutna i organska faza. Između 800 i 1000 °C dolazi do gubitka gotovo 10 % mase uzorka zbog pretvorbe bakrova(II) oksida u bakrov(I) oksid. Morfologija uzorka može se opisat kao homogeni pahuljasti aglomerati CuO nanočestica. Antimikrobna svojstva nanočestica bakrova(II) oksida određena su na bakterijama Pseudomonas aeruginosa i Bacillus subtilis nakon 24 h, te na gljivicama Candida albicans i Aspergillus niger nakon 72 h određivanjem zone inhibicije.In this work, copper(II) oxide nanoparticles were prepared and characterized. Synthesis of copper(II) oxide nanoparticles as accomplished using the sonochemical method. In order to gain insight into the composition and properties of the obtained sample, the sample was subjected to various analyses. The crystal structure and size of the crystallites were determined by X-ray diffraction analysis, the sample was also analyzed by infrared spectroscopy with Fourier transformation, thermogravimetric analysis, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and the size and shape of the particles were investigated with atomic force microscopy. The existence of one phase in the sample, identified as copper(II) oxide, with crystallite size up to 20 nm as confirmed. TGA analysis showed that a small part of precursor organic phase is present in the sample. Almost 10 % of the mass of the sample is lost to the chemical transformation of copper(II) oxide to
copper(I) oxide between 800 and 1000 °C. The morphology of the sample consists of homogeneously distributed fluffy-looking agglomerates of CuO nanoparticles. Antimicrobial properties of copper(II) oxide nanoparticles were determined on the bacteria Pseudomonas aeruginosa and Bacillus subtilis after 24 h, and on the fungi Candida albicans and Aspergillus niger after 72 h
Dependence of protective properties of water-based coating on method of exposure to environment
No full textKorozija predstavlja značajan problem za očuvanje kulturne baštine, a izloženost korozivnom okolišu može uzrokovati ozbiljno oštećenje ovih objekata. Korištenje premaza jedna je od brojnih metoda koje se danas provode kako bi se metalne konstrukcije zaštitile od korozije. Iako mnogi premazi osiguravaju dobru zaštitu, njihovo korištenje može doprinjeti onečišćenju okoliša zbog emisije hlapivih organskih tvari. S ciljem korištenja ekološki prihvatljivijeg rješenja za zaštitu metalnih materijala, u ovom radu ispitivana su svojstva vodorazrjedivog akrilatnog premaza na brončanoj površini u tri korozivna okoliša. Ispitivanja su provedena na uzorcima koji su bili kontinuirano ili ciklički izlagani simuliranoj kiseloj kiši, kao i vlažnoj komori u vremenskom periodu od 22 dana. Uzorci su periodički karakterizirani elektrokemijskim tehnikama - metodama linearne polarizacije i elektrokemijske impedancijske spektroskopije. Iz dobivenih rezultata je zaključeno da kod kontinuiranog izlaganja dolazi do pada zaštite u vremenu dok kod cikličko izlaganja dolazi do porasta korozijske zaštite.Corrosion represents a significant problem for the preservation of cultural heritage and exposure to a corrosive environment can cause the serious damage to these objects. The application of coatings is one of the many methods used today to protect metal structures from corrosion. Although many coatings provide good protection, their widespread use can contribute to environment pollution due to the emission of volatile organic compounds. With the aim of using a more environmentally friendly solution for protection of metallic materials, in this work, the properties of acrylic waterborne coating on a bronze surface were examined in three corrosive environments. Measurements were conducted on samples that were either continuously or periodicaly immersed in simulated acid rain or exposed in condensation chamber over a period of 22 days. Samples were periodically characterized by electrochemical techniques –linear polarization method and electrochemical impedance spectroscopy. The obtained results showed that continuous exposure results in decrease of corrosion protection in time while cyclic exposure resulted in increase of corrosion protection
Alternatives to lithium batteries as a way of storing electrochemical energy
No full textStrelovit napredak mobilne tehnologije i nastojanja da se potrošnja fosilnih goriva zamijeni obnovljivim izvorima energije višestruko su povećali potrebu za sustavima koji pohranjuju električnu energiju. Proizvodnja trenutno najnaprednijeg sustava, litij-ionske baterije, eksponencijalno i neodrživo raste, a čak ni ona više nije dostatna za rastuće potrebe novih tehnologija. Zato se posljednjih godina istražuju brojni alternativni sustavi. U ovom radu navedeni su principi djelovanja, prednosti i nedostatci nekoliko vrsta baterijskih sustava koji pokazuju potencijal da u skoroj ili daljoj budućnosti postanu alternativa litij-ionskim baterijama : natrijeve, magnezijeve, cinkove, kalijeve, kalcijeve i aluminijeve baterije.The rapid progress of mobile technology and efforts to replace the consumption of fossil fuels with renewable energy sources have significantly increased the need for energy storage systems. The production of the currently most advanced system, lithium-ion battery, is exponentially and unsustainably growing, and is no longer sufficient for the growing demands of new technologies. Therefore, in recent years, numerous alternative systems have been explored. This paper presents the principles of operation, advantages and disadvantages of several types of battery systems that show the potential to become alternatives to lithium-ion batteries in the near or distant future: sodium, magnesium, zinc, potassium, calcium and aluminum batteries
Reduction of carbon dioxide emissions using adsorption processes
No full textZnatne emisije CO2 u atmosferu doprinose globalnom zagrijavanju što uzrokuje niz ekoloških problema. Smanjenje emisija CO2 ključno je za očuvanje okoliša i budućnosti naše planete, stoga ih je potrebno ograničiti u najvećoj mjeri. Svrha ovog rada je analiza procesa adsorpcije kao potencijalnog načina za smanjenje emisije CO2. Adsorpcija je proces u kojem se tvari(u ovom slučaju CO2) akumuliraju na površinu materijala(adsorbenta) kako bi se smanjila njegova koncentracija u okolišu. Uporaba adekvatnih adsorbenata može biti ključna za uspješnu adsorpciju CO2, a jedni od najkorištenijih su zeolit, aktivni ugljen i
metal-organski okviri(MOF). Maksimalna količina adsorbata koja se može vezati na površini adsorbenta može se prikazati adsorpcijskim izotermama u ovisnosti o tlaku. Proces adsorpcije može se primijeniti u različitim industrijama, ali ponajviše u petrokemijskoj jer izgaranje fosilnih goriva je glavni krivac povećanju emisije CO2. S ciljem smanjenja emisije CO2, u ovom radu proučavane su metode adsorpcije s promjenom temperature (TSA), s promjenom tlaka (PSA) i u vakuumskim uvjetima (VSA) koji se provode cikličkim šaržnim radom s fiksnim slojem adsorbenta. U TSA, veća čistoća i učinkovitost se postiže povećanjem temperature adsorpcije i desorpcije te korištenjem MOF-74 u odnosu na zeolit i aktivni ugljen, dok za veću razinu koncentracije CO2 je bolje primijeniti zeolit. Prednosti TSA metode su visoka selektivnost adsorpcije i mogućnost regeneracije adsorbenta. U PSA procesu, pri visokom tlaku, CO2 se adsorbira na površini čvrstog adsorbenta, a zatim se promjenom tlaka na nižu vrijednost, oko atmosferskog tlaka, desorbira s adsorbenta i otpušta se za daljnji transport. PSA metoda također omogućuje visoku selektivnost adsorpcije i mogućnost regeneracije adsorbenta, jednostavnog je dizajna. Komercijalno je izvediva tehnologija za izdvajanje CO2 u termoelektranama zbog niskih energetskih zahtjeva i niskih investicijskih troškova s učinkovitošću od 84% i više. VSA je tehnika adsorpcije koja se temelji na promjeni vakuumskih uvjeta. Adsorbent se koristi za adsorpciju CO2 pri povišenom tlaku, a zatim se stvara vakuum kako bi se oslobodio CO2. Ova metoda omogućuje rad pod nižim tlakovima te visoku selektivnost adsorpcije. S druge strane, VPSA, koristi kombinaciju VSA i PSA te se smjesa plinova dovodi pod povišeni tlak i prolazi kroz adsorbent koji selektivno adsorbira CO2, a nakon što se tvar adsorbirala se stvara vakuum kako bi se adsorbirana tvar oslobodila.Large amounts of CO2 emissions contribute to global warming and have adverse effects on the atmosphere. The purpose of this study is to research and analyse the process of adsorption as a potential method for reducing CO2 emissions. Adsorption is a process in which substances (in this case, CO2 ) accumulate on the surface of a material (adsorbent) to reduce its concentration in the environment. The use of suitable adsorbents can be crucial for successful CO2 adsorption, with commonly used ones being zeolite, activated carbon, and metal organic frameworks (MOFs). The maximum amount of adsorbate that can be bound to the adsorbent's surface can be represented by adsorption isotherms as a function of pressure. The process of adsorption can be applied in various industries, particularly in petrochemicals, as the combustion of fossil fuels is a major contributor to increased CO2 emissions. To reduce CO2 emissions, this study examines temperature swing adsorption (TSA), pressure swing adsorption (PSA), and vacuum swing adsorption (VSA) methods, which are conducted through cyclic batch operation with a fixed bed. In TSA, higher purity, CO2 recovery, and efficiency are achieved by increasing the adsorption and desorption temperature and using MOF-74 compared to zeolite and activated carbon, while zeolite is preferable for higher CO2 concentration levels. The advantages of the TSA method include high selectivity of adsorption and the ability to regenerate the adsorbent. In the PSA process, CO2 is adsorbed on the surface of a solid adsorbent at high pressure and then desorbed from the adsorbent by lowering the pressure to around atmospheric pressure for further release and transport. The PSA method also allows for high selectivity of adsorption and the ability to regenerate the adsorbent, and it is a commercially viable technology for CO2 separation in power plants due to its low energy requirements and investment costs, with efficiencies of 84% and above. VSA is a technique based on changing vacuum conditions, where an adsorbent is used to adsorb CO2 at elevated pressure, and then a vacuum is created to release the CO2 . This method enables operation under lower pressures and high selectivity of adsorption. On the other hand, VPSA combines VSA and PSA, where the gas mixture is brought to elevated pressure and passes through an adsorbent that selectively adsorbs CO2 , and after adsorption, a vacuum is created to release the adsorbed substance
Active packaging based on biopolymers for food packaging
No full textAmbalažni materijali za pakiranje hrane imaju velik značaj u očuvanju kvalitete i roka trajanja hrane. Tako, polimerni materijali omogućuju zamrzavanje hrane i time značajno produljuju vijek njezina trajanja uz zadržavanje nutritivnih vrijednosti. Nadalje, to doprinosi kvaliteti prehrambenih navika i hrana nije samo sezonska već ju je moguće konzumirati kroz cijelu godinu. Također, značaj doprinos u smanjenju bacanja hrane i nastajanja biootpada jer usporava proces kvarenja. Stoga, je ambalažna za pakiranje hrane predmet stalnih istraživanja. Ambalažni materijali za pakiranje hrane predstavljaju veliki problem nakon upotrebe zbog otežanog recikliranja tankih, često višeslojnih plastičnih materijal. Stoga, biopolimeri predstavljaju kvalitetnu zamjenu, kao materijali za pakiranje hrane budući da su biorazgradljivi. Kako bi se podigla kvaliteta ambalažnih materijala za pakiranje hrane s ciljem usporavanja proces kvarenja u bioplimerne filmove dodaju se aktivne tvari, pri čemu nastaje aktivna ambalaža. U ovom radu opisuju se različiti ambalažni materijali kao i njihova svojstva. Upoznaju se najznačajniji sintetski i biopolimeri koji se koriste za proizvodnju ambalaže za pakiranje hrane.Packaging materials for food packaging are of great importance in preserving the quality and shelf life of food. Thus, polymer materials allow food to be frozen and thereby significantly extend its shelf life while retaining its nutritional value. Furthermore, it contributes to the quality of eating habits and food is not only seasonal but can be consumed throughout the year. Also, a significant contribution to the reduction of food waste and the creation of biowaste because it slows down the spoilage process. Therefore, packaging for food packaging is the subject of constant research. Packaging materials for food packaging represent a big problem after use due to the difficulty of recycling thin, often multi-layered plastic materials. Therefore, biopolymers represent a quality substitute, as materials for food packaging, since they are biodegradable. In order to improve the quality of packaging materials for food packaging with the aim of slowing down the spoilage process, active substances are added to biopolymer films, resulting in active packaging. This paper describes different packaging materials as well as their properties. The most important synthetic and biopolymers used for the production of packaging for food packaging are introduced
Extraction of organic pollutants from soil by soil solid-phase dispersion
No full textU ovom radu razvijena je metoda ekstrakcije organskih zagađivala, policikličkih aromatskih ugljikovodika, polikloriranih bifenila te organoklorovih pesticida iz uzoraka tla raspršenjem tla kroz čvrstu fazu. Spojevi su to koji pokazuju izrazito negativne učinke na sve sastavnice okoliša što je posljedica njihove toksičnosti, dugotrajne postojanosti te lipofilne prirode koja uzrokuje njihovu migraciju iz vodenog medija u tlo. Iz tog razloga bitno je kvalitativno i kvantitativno odrediti navedene spojeve što je preduvjet za praćenje njihove prisutnosti i kretanja u okolišu. Metode kemijske analize koje se koriste u tu svrhu moraju biti izrazito osjetljive budući da se radi o nižim koncentracijama. Samim time i uzorci koji se analiziraju moraju biti visoko koncentrirani i čisti što zahtijeva dodatnu pripremu. U tu svrhu provedena je ekstrakcija raspršenjem tla kroz čvrstu fazu na kontrolnom uzorku tla. Parametri koji su se optimirali su: izbor čvrste faze (sorbensa), omjer tla i sorbensa te otapalo za eluiranje. Obzirom na dobivena iskorištenja, najboljim sorbensom pokazala se dijatomejska zemlja, najboljim omjerom tla i sorbensa omjer 1:4, a najboljim otapalom smjesa acetona i heksana u omjeru 1:1. Takva optimirana i validirana metoda primjenjena je na 10 realnih uzoraka tla iz okolice Zagreba. Dobivene vrijednosti koncentracija sve su redom niže od maksimalne dopuštene koncentracije koja je propisana Pravilnikom o zaštiti poljoprivrednog zemljišta od onečišćenja (NN 9/2014).In this paper, the extraction of organic pollutants from soil samples by dispersing the soil with the solid phase was studied. Specifically, polycyclic aromatic hydrocarbons, polychlorinated biphenyls and organochlorine pesticides were extracted. These are compounds that have extremely negative effects on all components of the environment, due to their toxicity, long-term stability and lipophilic nature, which causes the migration of the above pollutants from the water medium to the soil. For this reason, it is important to qualitatively and quantitatively determine the mentioned compounds, which in turn is then a prerequisite for monitoring their presence and movement in the environment. The chemical analysis methods used for this purpose must be extremely sensitive, since low concentrations are involved. Therefore, the samples for analysis must be highly concentrated and pure, which requires additional preparation. For this purpose, extraction was performed by dispersing a control soil sample with soil through the solid phase. The parameters that were optimized are: solid phase (sorbent), ratio of soil to sorbent and solvent for elution. Considering the obtained yields, the best sorbent was diatomaceous earth, the best ratio of soil to sorbent was 1:4, and the best solvent was a mixture of acetone and hexane in the ratio 1:1 This optimized and validated method was applied to 10 real soil samples from the surroundings of Zagreb. The obtained concentration values are all below the maximum value required by law
Enzyme immobilisation on silanized magnetic nanoparticles functionalised by (3-aminopropyl)trimethoxysilane
No full textEnzim deoksiriboza-5-fosfat aldolaza (DERA) katalizira reakciju dvostruke aldolne adicije dvije molekule acetaldehida i jedne molekule kloracetaldehida. Spomenuta reakcija koristi se , prilikom sinteze prekursora u proizvodnji statina. Visoka koncentracija aldehida u DERA kataliziranoj reakciji negativno utječe na stabilnost enzima. Cilj ovog rada bio je provesti imobilizaciju enzima DERA-e na magnetske nanočestice u svrhu povećanja njegove stabilnosti. Magnetske nanočestice obložene su silikom po Stöberovom procesu te funkcionalizirane APTMS-om ((3-aminpropil)trimetoksisilanom)). Za aktivaciju su korištena tri aktivacijska sredstva: benzokinon, glutaraldehid i sukcinski anhidrid različitih koncentracija. Najbolji parametri uspješnosti procesa imobilizacije dobiveni su prilikom korištenja nosica aktiviranim s 15 %-tnim sukcinskim anhidridom kao aktivacijskog sredstva, te je taj korišteno u daljnjim ispitivanjima. Isto tako, poznato je da pH vrijednost pufera i temperatura prilikom procesa imobilizacije enzima mogu imati veliki utjecaj na aktivnost enzima, pa tako i na uspješnost procesa imobilizacije. Stoga, ispitan je utjecaj pH i temperature prilikom procesa imobilizacije enzima DERA-e. Najveća efikasnost i iskorištenje postignuti su pri temperaturi od 30 °C i pH 6.Deoxyribose-5-phosphate aldolase (DERA) catalyzes the reaction of the double aldol addition of two acetaldehyde molecules and one chloroacetaldehyde molecule. The mentioned reaction is used in the synthesis of precursors for the production of statins. The high concentration of aldehyde in the DERA catalyzed reaction negatively affects the stability of the enzyme. The aim of this work was to immobilize the DERA enzyme on magnetic nanoparticles to increase its stability. Magnetic nanoparticles were coated with silica using the Stöber method and functionalized with APTMS ((3-aminopropyl)trimethoxysilane)). Three activation agents were used: benzoquinone, glutaraldehyde and succinic anhydride at different concentrations. The higest efficiency for the immobilization process were obtained when the carrier was activated with 15 % succinic anhydride, so this carrier was used in further tests. It is known that the pH of buffers and temperature during the process of enzyme immobilization can have an impact not only on the activity of enzymes, but also on the success of the immobilization process. Therefore, the influence of pH and temperature during the immobilization process of DERA enzyme was also investigated. The highest efficiency and yield were achieved at a temperature of 25 °C and a pH of 6
Determination of solubility and characterization of the active pharmaceutical ingredient
No full textFarmaceutska industrija je danas jedna od najrazvijenijih industrija. Podaci o topljivosti djelatne tvari i kemijskih međuproizvoda koji se koriste u farmaceutskoj industriji osnovni su podatci koji su potrebni za proces sinteze i pročišćavanja. Osim toga, s gotovo 40% spojeva koji se koriste kao lijekovi imaju problem s topljivosti. Stoga je svaki pokušaj predviđanja topljivosti vrlo važan u istraživanjima otkrivanja lijekova. U radu je određena topljivost dviju djelatnih tvari, dronedaron hidroklorida i ceritiniba u različitim otapalima i smjesama otapala. Dobiveni eksperimentalni podaci (dronedaron hidroklorid i ceritinib) te literaturni podaci (dronedaron hidroklorid) korelirani su različitim jednadžbama kao što su modificirana Apelblatova, Yawsova i Van’t Hoffova jednadžba. Sve jednadžbe dobro opisuju dobivene podatke, a bolje slganje esperimentalnih i računski određenih podataka ovisi o komponenti čija se topljivost određuje, rasponu ispitivanog temperaturnog područja, otapalu te eksperimentalnoj metodi.Today, the pharmaceutical industry is among the most advanced industries. Data on the solubility of the active substance and chemical intermediates used in the pharmaceutical industry are the fundamental data required for the synthesis and purification process. In addition, nearly forty percent of pharmaceutical compounds have solubility issues. Consequently, any attempt to predict solubility is crucial to drug discovery research. This study determined the solubility of two active substances, dronedarone hydrochloride and ceritinib, in various solvents and solvent mixtures. This study examined the solubility of two active compounds, ceritinib and dronedarone hydrochloride, in various solvents and solvent combinations. Dronedarone hydrochloride and ceritinib obtained from the experiments and Dronedarone hydrochloride from the literature were correlated using a variety of equations, including the modified Apelblat, Yaws, and Van't Hoff equations. The better agreement between experimental and computationally calculated data depends on the component whose solubility is determined, the range of the tested temperature range, the solvent, and the experimental method. All equations adequately describe the given data
Determination of true powder density by use of laboratory glassware
No full textCilj ovog rada bio je odrediti gustoću praška sastavljenog od staklenih kuglica modificiranom metodom piknometra. Budući da tekućinski piknometar ima jako usko grlo, nepraktičan je za rad s praškastim uzorcima te je u ovom radu gustoća staklenih kuglica određena korištenjem staklene bočice sa čepom i menzure od 10 mL kao improviziranih piknometara. Kao otapalo korišteni su destilirana voda i etanol, a gustoća staklenih kuglica određena je kao aritmetička sredina tri uzastopna mjerenja. Rezultati dobiveni korištenjem staklene bočice i vode kao otapala te korištenjem menzure i oba otapala odgovaraju teorijskoj vrijednosti gustoće od
2,5 g/cm^3. Pritom je najniža standardna devijacija od 0,1823 dobivena korištenjem menzure i vode kao otapala što je i očekivano budući da je menzura graduirano laboratorijsko posuđe za razliku od staklene bočice na kojoj je oznaka proizvoljno urezana dijamantnim nožićem. Na temelju dobivenih rezultata proizlazi da je predstavljena metoda određivanja gustoće staklenih kuglica pomoću improviziranog piknometra pouzdana i dobra alternativa klasičnom piknometru.The purpose of this work was to determine the density of powder consisting of glass beads using a modified pycnometer method. Since the liquid pycnometer has a very narrow neck, it is impractical for working with powder samples. Therefore in this work the density of glass beads was determined using a glass vial with a stopper and a 10 mL graduated cylinder as improvised pycnometers. Distilled water and ethanol were used as solvents, and the density of glass beads was determined as the arithmetic mean of three consecutive measurements. The results obtained using the glass vial and water as solvent and using the graduated cylinder and both solvents correspond to the theoretical density value of 2,5 g/cm^3.
At the same time, the lowest standard deviation of 0,1823 was obtained using the graduated cylinder and water as solvent, which is expected since the cylinder is a graduated laboratory vessel, unlike the glass vial on which a mark is arbitrarily engraved with a diamond knife. Based on the obtained results, the presented method of determining the density of glass balls using an improvised pycnometer is a reliable and good alternative to the classic pycnometer