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Chemical profile of volative compounds from marine sponge Petrosia fisiformis (Poiret, 1789) : master thesis
No full textSpužve su vrlo jednostavno građene mnogostanične životinje. Morska spužva Petrosia ficiformis (Poiret, 1789) spada u razred kremenorožnjača te je rasprostranjena duž cijele obale Sredozemnog mora i Makaronezije. Cilj ovoga rada bio je izolirati i analizirati isparljive spojeve spužve P. ficiformis. Pregledom literature nisu pronađena opsežna istraživanja na ovoj spužvi. Stoga, u ovome radu se nastojalo dobiti što potpuniji uvid u kemijski profil isparljivih spojeva navedene spužve. Isparljivi spojevi svježe i na zraku sušene P. ficiformis, uzorkovane na poluotoku Rtina kod Paškog mosta, dobiveni su hidrodestilacijom u modificiranoj aparaturi po Clevengeru i mikroekstrakcijom vršnih para na čvrstoj fazi koristeći dva vlakna (HS-SPME). Analiza svih uzoraka provedena je vezanim sustavom plinska kromatografija - spektrometrija masa na HP-5MS koloni. Identificiran je ravnolančani zasićeni alifatski ugljikovodik heptadekan (C 17 H 36 ) kao dominantan spoj na oba vlakna. Jedino je u svježem uzorku na DVB/CAR/PDMS vlaknu oktan-3-ol bio u većem postotku. Također, na oba vlakna u svježim i suhim uzorcima, derivati benzena čine kvantitativno važne skupine s benzaldehidom i benzil-alkoholom kao glavnim komponentama. U destilatu alifatski spojevi su bili s najvećim udjelom. Spojevi s najvećim udjelom u svježem uzorku su okt-1-en-3-ol i diizobutil-ftalat, dok je u suhom uzorku najveći udio dimetil-trisulfida i indola.Sponges are very simply built multicellular animals. The sea sponge Petrosia ficiformis (Poiret, 1789) belongs to the class of Demospongiae and can be found along the entire coast of the Mediterranean Sea and Macaronesia. The aim of this diploma thesis was to isolate and analyze the volatile compounds of the sponge P. ficiformis. Extensive research on this topic was not found in the literature. Therefore, an attempt was made to obtain a more complete profile of volatile compounds from this sponge. Volatile compounds of fresh and air-dried P. ficiformis, sampled on Rtina peninsula near the Pag bridge, were obtained by hydrodistillation in a modified Clevenger apparatus and by headspace-solid phase microextraction on two fibers (HS-SPME). The analysis of all samples was performed by coupled gas chromatography - mass spectrometry on an HP-5MS column. A straight-chain saturated aliphatic hydrocarbon, heptadecane (C 17 H 36 ), was identified as the dominant compound on both fibers. Only octan-3-ol had a higher abundance in the fresh sample on DVB/CAR/PDMS fiber. Also, on both fibers in both fresh and air-dried samples, benzene derivatives formed quantitatively important groups with benzaldehyde and benzyl alcohol as the major compounds. In the distillate, the aliphatic compounds are the group with the largest percentages. The compounds with the highest percentage in the fresh sample were oct-1-ene-3-ol and diisobutyl phthalate, while dimethyl trisulfide and indole were the most abundant in the dry sample
Activity assessment of solar cells based on nanocrystalline ZnO under different conditions of active film preparation : master thesis
No full textU radu je ispitivana aktivnost solarnih ćelija s fotoosjetljivim bojilom (DSSC) na bazi nanokristaličnog cink (II) oksida na način da je fotoinducirani napon ćelija mjeren pri umjetnom osvjetljenju i pri sunčevoj svjetlosti tijekom 10 dana. Pasta nanokristaličnog ZnO pripremljena je uobičajenim postupkom bez primjene kiseline. Konzinstencija paste podešena je dodatkom etilnog alkohola i sredstva za poboljšanje kvašenja, neionskog disperganta Triton-X 100. Cilj je bio dobiti kompaktan porozni sloj koji dobro prijanja na površinu vodljivog stakalca. Stakalca s nanesenim slojem nanokristaličnog ZnO termički su obrađena te su nakon obrade uronjena u pripremljenu otopinu antocijanina ekstrahiranog iz suhog cvijeta hibiskusa, kojem je određen UV-Vis spektrogram. Na vodljivu stranu stakalaca za katode solarnih ćelija nanesen je sloj grafita metodom prskanja te su potom katode sušene radi uklanjanja organskog otapala. Stakalca s nanesenim tankim slojem nanočestica ZnO te stakalca s nanesenim slojem grafita proučavana su digitalnim mikroskopom prije i poslije termičke obrade. U fotoćelije su dodavani komercijalni elektrolit te elektroliti pripravljeni na osnovi I 2 i KI otopljenih u etilen-glikolu i tetraetilen-glikolu. Rezultati pokazuju visoku aktivnost fotoćelija i uz umjetno osvjetljenje i na sunčevoj svjetlosti, bez potrebe za dodatkom nove količine elektrolita i do 9 dana.In this paper, the activity of dye-sensitized solar cells (DSSCs) based on nanocrystalline zinc(II) oxide was analyzed by measuring the photo-induced voltage of the cells under artificial lighting and under sunlight over a period of 10 days. The nanocrystalline ZnO paste was prepared by the usual process without the use of acid. The consistency of the paste was adjusted by the addition of ethyl alcohol and a wetting agent, the nonionic dispersion of Triton-X 100. The goal was to obtain a compact porous layer that adheres well to the surface of conductive glass. The conductive side of solar cells with an applied layer of nanocrystalline ZnO was thermally treated and, after the treatment, was immersed in a prepared solution of anthocyanin extracted from a dry hibiscus flower, for which the UV-Vis spectrogram was determined. A layer of graphite was applied to the conductive side of solar cells using the spraying method, and then the cathodes were dried to remove the organic solvent. Glasses with a thin layer of ZnO nanoparticles and glasses with a graphite layer were analyzed with a digital microscope before and after the thermal processing. Commercial electrolytes and electrolytes prepared on the basis of I 2 and KI dissolved in ethylene glycol and tetraethylene glycol were added to the photocells. The results show a high activity of the photocells both with artificial lighting and in the sunlight, without the need to add a new amount of electrolyte for up to 9 days
Digestive supplements for athletes and recreationists : bachelor thesis
No full textDanas se sve više istraţuje prehrana sportaša. S obzirom na veću energetsku potrošnju, fizički aktivne osobe imaju i povećane nutritivne zahtjeve. Dobro balansiran odnos makro- i mikronutrijenata i adekvatna hidratacija mogu značajno unaprijediti sportsku izvedbu i odigrati ključnu ulogu u postizanju što boljih rezultata. Sportaši i rekreativci se sve više odlučuju na dodatke prehrani, kako bi organizmu osigurali sve potrebne nutrijente. Dodacima prehrani smatraju se pripravci s hranjivim ili fiziološkim učinkom koji imaju svrhu dodatno obogatiti uobičajenu prehranu u cilju odrţavanja zdravlja. Direktivom 2002/46/EZ dane su opće odredbe o usklaĎivanju zakona drţava članica u odnosu na dodatke prehrani. Danas na trţištu postoje različiti dodaci prehrani koji su opisani u ovom radu. U sklopu završnog rada obavljena je i anketa pod nazivom „Istraţivanje korištenja dodataka prehrani kod rekreativaca i sportaša u Republici Hrvatskoj“ kako bi se dao uvid u učestalost korištenja dodataka prehrani u fizički aktivnih osoba te o kojoj vrsti dodataka prehrani se radi. TakoĎer se ispitalo imaju li dodaci prehrani utjecaj na sportske rezultate.Sports nutrition is a frequent research topic nowadays. Since athletes need energy to meet the demands of physical activity and training, nutrition is essential for supporting their health. A balanced diet of macronutrients and micronutrients and adequate hydration can enhance sporting performance. Thus, a large number of athletes and recreationists take food supplements in order to gain all the necessary nutrients. Dietary supplements are substances with a nutritional and physiological effect whose aim is to enrich a daily diet and to preserve health. The reference EU legislation in the area of food supplements is Directive 2002/46/EC, which establishes harmonised lists of the vitamins and minerals substances used in the manufacture of food supplements. Nowadays, dietary supplements come in a variety of forms which are presented in this study. Moreover, this paper included a questionnaire which gave us insight into the use of supplements among physically active people. The information is provided under the heading The use of dietary supplements among Croatian athletes and recreationists
Catalysts used in biodiesel syntesis : bachelor thesis
No full textBiodizel, alternativa fosilnom dizelu, dobiva se procesom transesterifikacije, odnosno alkoholize. Transesterifikacija je reakcija zamjene alkoksilnih skupina u kojoj jedan ester prelazi u drugi. Postojeći komercijalni procesi dobivanja biodizela uglavnom se zasnivaju na homogeno-bazno kataliziranoj transesterifikaciji biljnih ulja. Zbog niske cijene i visoke reaktivnosti najčešće se kao katalizatori primjenjuju NaOH i KOH. Nedostatak ovoga procesa je saponifikacija te neučinkovito odvajanje katalizatora iz reakcijske smjese. U zadnje se vrijeme vrlo intenzivno istražuju heterogeni katalizatori, zbog sigurne uporabe i mogućnosti njihova recikliranja. Najviše je u uporabi CaO. Enzimi kao katalizatori najnovije generacije do sada su pokazali izuzetnu aktivnost u katalitičkoj reakciji, ali zbog visoke cijene i rizika deaktivacije njihov potencijal nije iskorišten u industriji. Tipičan primjer postupka transesterifikacije s homogenim katalizatorom je Lurgijev postupak, a s heterogenim katalizatorom Esterfip-H proces.Biodiesel is an alternative to fossil diesel, obtained through the process of transesterification, i.e. alcoholysis. Transesterification is a reaction of replacement of alkoxy groups of alcohols when one ester converts to another. Existing commercial biodiesel production processes are mainly based on homogeneous base-catalyzed transesterification of vegetable oils. Due to the low price and high reactivity, NaOH and KOH are most often used as catalysts. Disadvantage of this process is saponification and ineffective separation of the catalyst from the reaction mixture. Recently, heterogeneous catalysts have been extensively researched, due to their safe use and the possibility of their recycling. CaO is most commonly used. Enzymes as catalysts have so far shown exceptional activity as catalysts, but due to their high price and risk of deactivation, they haven't been used as much in the industry. A typical example of the transesterification process with a homogeneous catalyst is the Lurgi process, and with a heterogeneous catalyst the Esterfip-H process
Hg(II) sorption on sulfur-impregnated natural zeolite clinoptilolite - determination of sorption mechanism : bachelor thesis
No full textPrirodni zeolit klinoptilolit je kemijski modificiran s otopinom Na 2 S pri 150 °C. Ispitana su sorpcijska svojstva polaznog uzorka, prirodnog zeolita klinoptilolita te dobivenog sumporom- impregniranog prirodnog zeolita prema ionima Hg(II) pri unaprijed definiranim optimalnim uvjetima, pH o =2 i omjeru kruto/tekuće 10 g/L. Maksimalni dobiveni kapacitet sorpcije sumporom-impregniranog prirodnog zeolita prema Hg(II) iznosi 1,02 mmol/g što je za 3,6 puta više u usporedbi s prirodnim zeolitom (0,28 mmol/g). Sorpcijski mehanizam Hg(II) na sumporom-impregniranom prirodnom zeolitu uključuje elektrostatsko privlačenje, ionsku izmjenu i površinsko kompleksiranje uz koprecipitaciju Hg(II) u obliku HgS što je potvrđeno određivanjem količine izmjenjivih zeolitnih kationa kao i SEM- EDS i TG-DTG analizom živom zasićenog sumporom-impregniranog prirodnog zeolita.Natural zeolite clinoptilolite is chemically modified with Na 2 S solution at 150 °C. The sorption properties of the initial sample, natural zeolite clinoptilolite and the obtained sulphur- impregnated natural zeolite towards Hg(II) ions were tested under pre-defined optimal conditions, pH o =2 and a solid/liquid ratio of 10 g/L. The maximum obtained sorption capacity of sulphur-impregnated natural zeolite towards Hg(II) was 1.02 mmol/g, which is 3.6 times more compared to natural zeolite (0.28 mmol/g). The sorption mechanism of Hg(II) on sulphur-impregnated natural zeolite includes electrostatic attraction, ion exchange and surface complexation with coprecipitation of Hg(II) in the form of HgS, which was confirmed by determining the amount of exchangeable zeolite cations as well as SEM-EDS and TG-DTG analysis of mercury saturated sulphur-impregnated natural zeolite
Technology and analysis of craft beer "Brucošica" : master thesis
No full textPivo je jedno od najstarijih alkoholnih pića u svijetu, a sam postupak proizvodnje se tijekom stoljeća nije značajno mijenjao. Međutim, tehnološki napredak tijekom godina je omogućio da se proizvodnja piva unaprijedi u smislu poboljšanja arome i okusa. Posljednjih nekoliko godina se dogodila prava revolucija u proizvodnji piva u kojoj su ključnu ulogu imali proizvođači specijalnih i craft piva. Craft piva se obično proizvode u malim pivovarama po izvornim, tradicionalnim recepturama u ograničenim količinama, a jedna od njihovih glavnih karakteristika je da su nefiltrirana i nepasterizirana. Uz to, pridaje se velika važnost i samoj kvaliteti te autentičnosti, a sve češće se tijekom proizvodnje dodaju različite arome voća i biljaka koje doprinose jedinstvenosti i osebujnosti finalnog proizvoda. U ovom radu je osmišljeno i proizvedeno craft pivo „Brucošica“ pomoću „Grainfather“ sustava te se provela fizikalno – kemijska analiza istog. Dobiveno pivo odlikuju vrlo dobra organoleptička svojstva, dok je analiza istog pokazala blaga odstupanja od očekivanih vrijednosti ispitivanih parametara (prvenstveno IBU i EBC vrijednosti) čemu su najvjerojatniji razlog oksidacijski procesi.Beer is one of the oldest alcoholic beverages in the world, and the production process itself has not changed significantly over the centuries. However, technological progress over the years has made it possible to improve beer production in terms of improving aroma and taste. In the last few years, a real revolution has taken place in the production of beer, in which producers of special and craft beers have played a key role. Craft beers are usually produced in small breweries according to original, traditional recipes in limited quantities, and one of their main characteristics is that they are unfiltered and unpasteurized. In addition, great importance is also attached to the quality and authenticity itself, and more frequently, during production, different aromas of fruits and plants are added, which contribute to the uniqueness and distinctiveness of the final product. In this thesis, the craft beer "Brucošica" was designed and produced using the "Grainfather" system, and its physico – chemical analysis was carried out. The obtained beer is characterized by very good organoleptic properties, while its analysis showed slight deviations from the expected values of the examined parameters (primarily IBU and EBC values), the reason for which is oxidation processe
Influence of temperature on the corrosion behavior of tin in NaCl solution : master thesis
No full textPraćenjem vremenske promjene potencijala otvorenog strujnog kruga, primjenom polarizacijskih metoda te elektrokemijske impedancijske spektroskopije proučavano je korozijsko ponašanje kositra u 0.5 M NaCl otopini kod različitih temperatura (10, 20, 30 i 40 o C) i pH vrijednosti otopine (3.0, 5.5 i 8.5). Oštećenja na površini metala određena su optičkim mikroskopom. Najveću otpornost prema koroziji kositar pokazuje u NaCl otopini pri 20 o C i pH = 8.5. Pri ovim eksperimentalnim uvjetima zabilježena je najveća vrijednost polarizacijskog otpora, R p , zatim najpozitivnija vrijednost korozijskog potencijala, E kor , i potencijala depasivacije, E dp te najmanja vrijednost korozijske, i kor , i pasivacijske struje, i pas . Također smanjenjem temperature i porastom pH vrijednosti NaCl otopine smanjuju se lokalna oštećenja površine uzorka. Korozijska otpornost kositra u NaCl otopini posljedica je formiranja površinskog oksidnog sloja čija svojstva ovise o eksperimentalnim uvjetima (temperatura, pH vrijednost, vrijeme izlaganja). Naime, impedancijska mjerenja provedena na potencijalu otvorenog strujnog kruga pokazuju da je otpor oksidnog filma na kositru kod svih ispitivanih temperatura dosta visok (reda veličine nekoliko desetina k cm 2 ) te da raste s vremenom izlaganja, naročito u otopinama nižih temperatura. Paralelno s navedenim, vremenom lagano raste i debljina oksidnog filma (brzina porasta debljine oksida ne ovisi o temperaturi otopine). Rezultati svjetlosne mikroskopije potvrđuju nepovoljan utjecaj temperature na zaštitna svojstva površinskog filma na kositru pri prolongiranom izlaganju NaCl otopini.The corrosion behaviour of tin in 0.5 M NaCl solution at different temperatures (10, 20, 30 and 40 o C) and solution pH values (3.0, 5.5 and 8.5) was investigated by observing the variation of the open circuit potential with time, applying polarisation methods and electrochemical impedance spectroscopy. Damage on the metal surface was determined using an optical microscope. Tin exhibits the highest corrosion resistance in NaCl solution at 20 o C and pH = 8.5. Under these experimental conditions, the highest value of polarisation resistance, R p , was recorded, followed by the most positive value of corrosion potential, E kor , and depassivation potential, E dp , and the lowest value of corrosion, i kor , and passivation current, i pas . Lowering the temperature and increasing the pH of the NaCl solution reduces local damage to the surface of the sample. The corrosion resistance of tin in NaCl solution is a consequence of the formation of a surface oxide layer, the properties of which depend on the experimental conditions (temperature, pH, exposure time). Indeed, open circuit impedance measurements show that the resistance of the oxide film on tin is quite high (of the order of a few tens k cm 2 ) and that it increases with exposure time, especially in lower temperature solutions. In parallel, the thickness of the oxide film also increases slightly with time (the rate of increase of the oxide thickness does not depend on the temperature of the solution). The results of light microscopy confirm the unfavourable influence of temperature on the protective properties of the surface film on tin during prolonged exposure to NaCl solution
Isolation and quantization of glucosinolates from Lepidium meyenii (BRASSICACEAE) and Moringa oleifera (MORINGACEAE) plants : diploma thesis
No full textGlukozinolati su sekundarni biljni metaboliti β-tioglukozidne strukture koji hrani biljnog podrijetla daju aromu, miris i okus. Smatraju se fitokemikalijama što znači da imaju potencijal u prevenciji različitih bolesti u ljudskom organizmu, a naročito pojave karcinoma. U ovom radu provela se identifikacija glukozinolata, te kvantizacija glukozinolata u prahu žutog i crvenog korijena Mace te Moringa praha i čaja. Lepidium meyenii (Brassicaceae) - Maca je bogata hranjivim elementima velike vrijednosti i sekundarnim metabolitima visoke biološke aktivnosti. U ovom radu određen je glukozinolatni profil iz dvije biljne vrste L. meyenii, žute i crvene. Kromatogram potvrđuje činjenicu da su prisutni slični glukozinolati. Glukotropeolin (benzil-glukozinolat) je u oba uzorka glavni pri čemu njegova količina u žutoj iznosi 7,02 μmol/g, a u crvenoj 8,96 μmol/g suhog biljnog materijala. Glukotropeolin je praćen s glukolimnantinom (3-metoksibenzil-glukozinolat) čija koncentracija u žutoj iznosi 1,93 μmol/g, a u crvenoj 2,55 μmol/g suhog biljnog materijala. Moringa oleifera (Moringaceae), poznata kao Moringa, podrijetlom je iz sjeverozapada Indije. U Africi se često konzumira za samo-liječenje bolesnika koji su pogođeni dijabetesom, hipertenzijom ili HIV / AIDS-om. U Moringi kao glavni spoj izdvaja se glukomoringin (4-(α-L-ramnoziloksi)benzil-glukozinolat, zastupljen u čaju u količini od 29,23 μmol/g i prahu 21,78 μmol/g suhog biljnog materijala. Acetilirani izomeri glukomoringina u Moringi su zastupljeni u znatno manjim količinama.Glucosinolates are plant secondary metabolites of β-thioglucoside structure that are responsible for flavour, aroma and taste of foods of plant origin. They are considered phytochemicals which means that they have the potential to protect the human body from various diseases, especially with the onset of cancer. In this work, the identification of glucosinolates and the quantization of glucosinolates in the powder of yellow and red roots of Maca and Moringa powder and tea were examined. Lepidium meyenii (Brassicaceae) - Maca is rich in nutrients of high value and secondary metabolites with high biological activities. In this paper, the glucosinolate profile from two plant species Lepidium meyenii (Maca), yellow and red, is correct. The chromatogram exposes the fact that similar glucosinolates are present. Glucotropeolin (benzyl glucosinolate) is the main glucosinolate in both samples having 7.02 μmol/g of dry weight in yellow Maca powder, and 8.96 μmol/g of dry weight in red Maca powder. Glucotropeolin was followed by glucolimnanthine (3-methoxybenzyl-glucosinolate), having 1.93 μmol/g of yellow Maca powder and 2.55 μmol/g of red Maca powder. Moringa oleifera (Moringaceae), commonly known as Moringa, is native to north-western India. In Africa, it is often consumed for the self-treatment of patients affected by diabetes, hypertension or HIV / AIDS. Glucomoringin (4- (α-L-ramnosyloxy)benzyl glucosinolate was identified as the main compound in Moringa, with 29.23 μmol/g of dry tea weight and 21.78 μmol/g of Moringa powder. The acetylated isomers of glucomoringin in both Moringa samples were identified in much smaller amounts
Determination of equilibrium amount of cobalt ions adsorbed on egg shells (T=28 0C) : master thesis
No full textU ovom je diplomskom radu ispitana adsorpcija kobaltovih iona na ljuskama jaja u ovisnosti o različitim početnim koncentracijama otopina kobaltovih iona (4,488 mmol dm-3, 8,365 mmol dm-3, 11,427 mmol dm-3, 20,814 mmol dm-3 te 31,223 mmol dm-3) pri stalnoj temperaturi od 28°C, brzini miješanja od 200 okr min-1, u trajanju od 96 h. Kao adsorbens korištene su ljuske jaja promjera d < 125 µm dok su koncentracije kobaltovih iona u ravnotežnim otopinama određene spektrofotometrijski. Na temelju dobivenih rezultata može se zaključiti kako količina adsorbiranih kobaltovih iona (qe) poraste s porastom ravnotežne koncentracije kobaltovih iona u otopini (ce) te postiže vrijednost koja predstavlja ravnotežnu količinu adsorbiranih kobaltovih iona na ljuskama jaja u iznosu qe = 0,163 mmol g-1. Učinkovitost adsorpcije kobaltovih iona dostiže svoju maksimalnu vrijednost pri početnoj koncentraciji od 8,365 mmol dm-3 te iznosi 9,758 %, a nakon toga opada s porastom početne koncentracije kobaltovih iona u otopini. Uzimajući u obzir izračunate vrijednosti za koeficijent korelacije R2 može se zaključiti kako se adsorpcija kobalta na ljuskama jaja najbolje može opisati Langmuirovim adsorpcijskim modelom.In this diploma thesis the adsorption of cobalt ions on egg shells was studied depending on the different initial concentrations of cobalt ions solutions (4.488 mmol dm-3, 8.365 mmol dm-3, 11.427 mmol dm-3, 20.814 mmol dm-3, and 31.223 mmol dm-3) at a constant temperature of 28°C, stirring speed of 200 rpm for 96 h. Egg shells with diameter d < 125 m were used as adsorbent while the concentrations of cobalt ions in equilibrium solutions were determined spectrophotometrically. Based on the results obtained, it can be concluded that the amount of adsorbed cobalt ions (qe) increases with the increase of the equilibrium concentration of cobalt ions in solution (ce) reaching value of qe = 0.163 mmol g-1 that represents the equilibrium amount of adsorbed cobalt ions on egg shells. The adsorption efficiency of cobalt ions reaches its maximum value of 9.758 % at initial concentration of 8.365 mmol dm-3 and then decreases with the increase of initial concentration of cobalt ions in solution. Taking into account the calculated values of the correlation coefficient R2, it can be concluded that the adsorption of cobalt on egg shells can best be described by the Langmuir adsorption model
Shell and tube heat exchangers in rotary kiln inlet block cooling system for portland cement production : diploma thesis
No full textDiplomski rad obuhvaća rješenje sustava hlaĊenja ulaznog bloka rotacijske peći za proizvodnju Portland cementa. Ispitana je serija industrijskih višecijevnih (engl. shell&tube) izmijenjivaĉa topline s uĉvršćenim snopom cijevi, tip 1-2, u svrhu hlaĊenja mineralnog ulja kojim se podmazuju klizni ležajevi na ulaznom bloku peći. Cilj je utvrditi koji od ispitivanih industrijskih rekuperatora (MIT03-MIT10), tip 1-2, zadovoljava zadane radne uvjete. Raspored cijevi je u trokutu s korakom od 13 mm, a broj pregrada u plaštu se mijenja od 6 (MIT03-MIT05) do 9 (MIT06-MIT10). Rezultati ispitivanja ukazuju da je režim strujanja u plaštu laminaran (Re < Re, kr ), dok je strujanje vode u cijevima pri svim ispitivanim protocima u prijelaznom podruĉju (2300 Re 10 000). Ukoliko je potrebna površina za izmjenu topline manja u odnosu na raspoloživu površinu ispitivani višecijevni izmjenjivaĉi navedenih karakteristika zadovoljavaju za hlaĊenje kliznih ležajeva rotacijske peći.The work includes the solution of the entire cooling system of the rotary kiln for the production of Portland cement at the inlet block of the kiln. A series of industrial multi-tube heat exchangers (shell & tube) with fixed tube bundle, type 1-2, was tested for cooling mineral oil that lubricates the slide bearings at the inlet block of the kiln. The aim is to determine which of the tested industrial recuperators (MIT03-MIT10), type 1-2, meets the specified operating conditions. The tubes are arranged in a triangle with a step of 13 mm, and the number of baffles in the shell varies from 6 (MIT03-MIT05) to 9 (MIT06-MIT10). The test results show that the flow regime in the shell is laminar (Re < Re, kr ), while the water flow in the tubes, flows in the transition area in all tested tubes (2300 Re 10 000). If the required heat exchange area is smaller than the available area, the tested industrial shell & tube heat exchangers with the above mentioned properties are sufficient to cool the slide bearings of the rotary kiln