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A hybrid AI-driven knowledge-based expert system for optimizing gear design
Full text linkThis paper presents a hybrid knowledge-based expert system (KBES) designed to predict crack incubation and fatigue life in gear design, serving as both a research tool and an educational resource. While crack growth and initiation are well understood, crack incubation remains a challenging area. The presented expert system (KBES) integrates a novel mathematical model for crack incubation based on analogy and defect analysis principles with an optimization algorithm for gear design. The system uses genetic algorithms to optimize gear parameters, demonstrating a 5-10% deviation from experimental values in a specific gear design problem case study. Based on this KBES and a hybrid approach, we developed a learning environment based on an intelligent tutoring system (ITS) which serves older students (MSc and PhD) as a learning environment for the acquisition of knowledge and, above all, for the development of an in-depth understanding of the phenomena that occur both during incubation and initialization and during the further propagation of cracks in the root of the gear tooth, which is the basis for determining the lifespan of gear transmissions
The influence of cohumulone on thermodynamics of micellization of alkyl trimethyl ammonium bromide surfactants
Full text linkIn the present study, micellization of three cationic surfactants, dodecytrimethylammonium bromide (DTAB), tetradecytrimethylammonium bromide (TTAB), and hexadecyltrimethylammonium bromide (HTAB), in the presence and absence of cohumulone (CH), was carefully examined with a wide variety of methods. Critical micelle concentration (CMC) was determined using fluorescence (DTAB: 12.2 mM, CH added: 14.50 mMTTAB: 2.38 mM, CH added: 4.80 mMHTAB: 0.66 mM, CH added: 2.29 mM) and conductivity measurements. The thermodynamics of micellization was thoroughly examined using Isothermal Titration Calorimetry (ΔH°mic (kJ/mol) at 25 °C: DTAB: −1.48added CH: −1.57TTAB: −3.88added CH: −4.16HTAB: −7.98added CH: −7.19). The effect of cohumulone on micelle dimensions was observed with Dynamic light scattering (DLSDTAB: 4.2 nm, CH added: 8.1 nmTTAB: 3.6 nm, CH added: 5.9 nmHTAB: 3.9 nm, CH added: 5.4 nm). Based on these results, a description of the micellization of alkyltrimethylammonium bromide surfactants in the presence of CH was developed. While CMC and micellization thermodynamics remain virtually unaltered in the presence of CH, micelle size and its polydispersity get significantly increased, and the micelle formation process is notably changed
The problematic use of rap lyrics as evidence in criminal proceedings
Full text linkTo diplomsko delo obravnava problematiko uporabe rap besedil kot dokaznega gradiva v kazenskih postopkih v Združenih državah Amerike.
Najprej je bilo predstavljeno zgodovinsko in kulturno ozadje rap glasbe, predvsem gangsta rapa, saj je razumevanje značilnosti rap glasbe in okoliščin nastanka ključno za razumevanje celotne problematike. Zaradi uporabe nasilnih in kontroverznih motivov so rap izvajalci pogosto obravnavani kot realni odraz vsebine svojih besedil, kar tožilstva izkoriščajo za dokazovanje obtožb, četudi so besedila precej splošna. V nasprotju z drugimi umetniškimi žanri (npr. kriminalnimi romani, grozljivkami) se le rap dosledno uporablja kot dokazno gradivo, pogosto brez upoštevanja njegove umetniške narave in fikcije.
V nalogi so poleg splošne predstavitve sodne prakse uporabe rap besedil kot umetniških izdelkov podrobneje predstavljeni trije primeri, v katerih so rap besedila obravnavana kot: priznanje kaznivih dejanj, dokaz motiva ali namena ter kot grožnja, prav tako pa so predstavljeni tudi možni argumenti obrambe, da besedila izločijo iz dokazov.
Diplomsko delo opozarja na nevarnosti, ki jih taka praksa pomeni za pravico do svobodnega izražanja in poštenega sojenja ter poziva k strožjemu pravnemu nadzoru nad dopustnostjo umetniških vsebin kot dokazov. Namen raziskave je tudi opozoriti na morebitno širjenje takšne prakse v druge pravne sisteme, vključno s slovenskim, ter prispevati k širšemu razumevanju meja med umetnostjo in kazensko odgovornostjoThis thesis examines the issue of using rap lyrics as evidence in criminal proceedings in the United States.
It begins with an overview of the historical and cultural background of rap music, with a particular focus on gangsta rap, as understanding the characteristics of rap and the context of its creation is essential for grasping the broader legal problem. Due to the use of violent and controversial themes, rap artists are often perceived as literal representations of their lyrics, and prosecutors often exploit this narrative to support criminal charges, even when the lyrics are general or fictional. Unlike other artistic genres (e.g., crime novels, horror films), rap is uniquely and consistently treated as admissible evidence, often without proper consideration of its artistic nature or fictional context.
In addition to a general overview of case law regarding rap lyrics as artistic works, the thesis presents three specific cases in greater detail, in which rap lyrics were used respectively as: confessions to criminal acts, evidence of motive or intent, and as threats. It also outlines possible defense arguments for excluding such lyrics from evidence.
The thesis highlights the dangers this legal practice poses to the rights to freedom of expression and a fair trial and calls for stricter legal oversight of the admissibility of artistic content as evidence. The aim of the research is also to draw attention to the potential spread of this practice to other legal systems, including the Slovenian one, and to contribute to a broader understanding of the boundaries between art and criminal liability
Peppermint oil extraction and isolation ( mentha piperita)
No full textPri diplomski nalogi smo iz poprove mete, lat. Mentha piperita, izolirali eterična olja z različnimi kovnencionalnimi in nekonvencionalnimi metodami. Pri vseh ekstrakcijskih metodah smo uporabili tri topila, metanol, etanol in petroleter, z izjemo Clevengerjeve destilacije, kjer je topilo voda. Nato smo ekstrakte analizirali na vsebnost lahkohlapnih komponent in kvalitativno in kvantitativno določili sestavo olj s pomočjo plinske kromatografije z masno spektrometrijo. Identificiranih je bilo 71 komponent, v najvišjih deležih pa se v eteričnem olju pojavljajo mentol (37,7 %), menton (31,2 %), neomentol (3,3 %), piperiton (2,6 %) in mentil acetat (2,6 %). Ugotovljeno je bilo, da so bili najvišji izkoristki ektrakcij doseženi z ekstrakcijo po Soxhletu, čeprav so bili v splošnem izkoriski zelo nizki. Preučevali smo tudi vpliv topila na izkoristek ekstrakcije in ugotovili, da je najprimernejše topilo metanol, pri analizi vsebnosti pa lahko vidimo, da so se pri vseh treh topilih izločale enake glavne komponente. Poleg tega so rezultati pokazali, da so bile kemične sestavine eteričnih olj pri vseh metodah podobne z manjšimi količinskimi razlikami.For this thesis, we isolated essential oils from Mentha piperita, also known as peppermint, using various conventional and non-conventional methods. All extraction methods were carried out with three solvents, methanol, ethanol and petroleum ether, with the exception of Clevenger distillation, where the solvent was water. The extracts were then analysed for the content of volatile components and the composition of the oils was determined qualitatively and quantitatively by gas chromatography-mass spectrometry. Seventy-one components were identified, with menthol (37,7 %), menthone (31,2 %), neomenthol (3,3 %), piperitone (2,6 %) and menthyl acetate (2,6 %) occurring in the highest proportions in the essential oil. The highest extraction yields were found to be obtained with the Soxhlet extraction, although the yields were generally very low. The effect of solvent on the extraction yield was also investigated and methanol was found to be the most suitable solvent. From the analised data we can claim that the same main components were extracted with all three solvents. In addition, the results showed that the chemical constituents of the essential oils were similar in all methods with minor quantitative differences
Recycling of waste plastics using hydrothermal processes
No full textPoliolefini, med katerimi sta najbolj zastopana predstavnika polietilen (PE) in polipropilen (PP), so daleč največji razred sintetičnih polimerov, ki se danes izdelujejo in uporabljajo. Predstavljajo več kot 40 % letno proizvedene plastike, pri čemer se ta količina povečuje in s tem se povečuje tudi letna količina proizvedenih odpadkov. Da bi lahko ta odpadni material pretvorili v uporabne produkte, smo izvedli hidrotermično razgradnjo različnih materialov iz PE in PP z nadkritično vodo.
Hidrolizo smo izvedli na osnovnem in recikliranem HDPE pri različni temperaturi (425 °C in 450 °C ) in različnih reakcijskih časih (15 min do 240 min). Pri reakcijskih pogojih 450 °C in 60 min smo degradirali tudi ostale poliolefinske mešanice (metaloceniski LLDPE, dva reciklirana LDPE, dve mešanici granulata (MDPE+LLDPE in LDPE+rLDPE) in foliji iz teh dveh granulatov, folijo PP in vrečko iz LDPE materiala. Kot rezultat smo dobili produkte trdne, plinske, oljne in vodne faze. Trdne faze smo analizirali s Fourierjevo transformacijsko infrardečo spektrskopijo (FTIR), oljne in plinske faze smo analizirali s plinskim kromatografom z masnim spektrometrom (GC-MS) in vodne faze na analizatorju celokupnega ogljika (TOC).
Ugotovili smo, da pri kratkih reakcijskih časih nastajajo voski, medtem ko z daljšanjem reakcijskih časov dobimo oljne produkte. V vseh primerih belega ali prozornega granulata in prozorne folije, je nastalo manj kot 1 % ostanka. Več ostanka je nastalo v primeru materialov, ki so vsebovali aditive, torej pri vHDPE (1,57 %), rLDPE2 (1,43 %) in pri vzorcu vrečke (2,97 %).
Oljna faza predstavlja tudi glavni produkt razgradnje poliolefinov. Pri vseh vzorcih smo pri 450 °C in 60 min dobili izkoristek oljne faze višji od 89 %. Največji delež oljne faze pri polipropilenskem materialu so predstavljale aromatske spojine (46,77 %), med tem ko pa so v primeru polietilenskih materialov največji delež predstavljali nasičeni alifatski ogljikovodiki (med 50 % in 55 %).
Pri osnovnem in recikliranem HDPE smo ugotovili, da je izkoristek plinske faze naraščal z naraščanjem reakcijskega časa (pri osnovnem od 1,32 % do 25,62 % in pri recikliranem od 1,29 % do 29,23 %). Izkoristki ostalih poliolefinskih mešanic pri pogoju 450 °C in 60 min so bili med 4 % in 10 %. Plinske faze so bile o večini sestavljene iz krajših alkanov in alkenov (C1-C6), med katerimi prevladujeta etan in propan.
Najvišjo koncentracijo celokupnega ogljika v vodni fazi smo dokazali v primeru osnovnega HDPE materiala (2458 mg/L) pri 450 °C in 60 min.
Rezultati te študije kažejo, da nadkritična voda predstavlja dober reakcijski medij za pretvorbo odpadnih poliolefinov v uporabne produkte.Polyolefins, of which polyethylene (PE) and polypropylene (PP) are the most represented, constitute the largest class of synthetic polymers produced and used today. They represent more than 40 % of plastics produced each year, and this amount is increasing, so the amount of waste produced is also increasing. In order to be able to convert these waste materials into useful products, the hydrothermal decomposition of various materials from PE and PP with supercritical water was performed in this study.
Hydrolysis was done on virgin and recycled HDPE at different temperatures (425 °C and 450 °C) and different reaction times (15 minutes to 240 minutes). At the reaction conditions of 450 °C and 60 min other polyolefin mixtures (metallocene LLDPE, two recycled LDPE, two granulate mixtures (MDPE+LLDPE and LDPE+rLDPE) and foils made from these two granulates, PP foil and a bag made from LDPE material) were also degraded. As a result, products in the solid, gas, oil and water phases were obtained. The solid phases were analyzed by Fourier-transform infrared spectroscopy (FTIR), the oil and gas phases by gas chromatography–mass spectrometry (GC-MS) and aqueous phases by TOC analyser.
It was found that waxes were formed at shorter reaction times, while oily products are obtained at longer reaction times. In all cases of white or transparent granules and transparent film, less than 1 % of residue was formed. More residue occurred in materials containing additives, i.e. vHDPE (1,57 %), rLDPE2 (1,43 %) and the bag sample (2,97 %).
The oil phase is the main product of polyolefin decomposition. For all samples, the yield of the oil phase at 450 °C and 60 min was over 89%. Aromatic compounds accounted for the largest proportion of the oil phase from polypropylene material (46,77 %), while saturated aliphatic hydrocarbons accounted for the largest proportion from polyethylene materials (between 50 % and 55 %).
It was determined that the yield of the gas phase increased with increasing reaction time for virgin and recycled HDPE (from 1,32 % to 25,62 % for virgin material and from 1,29 % to 29,23 % for recycled HDPE). The yield of the gas phases of other polyolefin mixtures were between 4 % and 10 % at 450 °C and 60 min. The gas phases consisted mainly of shorter alkanes and alkenes (C1-C6), with ethane and propane dominating.
The highest concentration of total organic carbon in the water phase was found in the case of virgin HDPE material (2458 mg/L) at 450 °C and 60 min.
The results of this study show that supercritical water represents a good reaction medium for the conversion of waste polyolefins into useful products
Automation of co2 emptying machine
No full textDiplomsko zaključno delo opisuje potek gradnje avtomatiziranega stroja za praznjenje CO2 jeklenk. Gre za rotacijski stroj, gnan s pomočjo servo pogona, ki s pomočjo pnevmatskih cilindrov izprazni jeklenke ter jih preda polnilnemu stroju. Jeklenke, ki jih stroj ne uspe izprazniti v prvem ciklu, ter ki pridejo v stroj s prenizkim tlakom, se na izhodnem traku s pnevmatskim cilindrom izvržejo. Stroj se dejansko obnaša kot neke vrste stroj inšpektor, saj je tako omogočen ponoven proces visokotlačnega polnjenja s plinom CO2. Izpraznjen CO2 se skozi praznilni ventil in odzračevalni kanal odzrači s pomočjo ventilatorja. Proces je opisan od začetnih pomembnih konstrukcijskih lastnosti pa vse do njegove elektro-programske rešitve.The diploma thesis describes the construction process of an automated CO2 cylinder emptying machine. It is a servo-driven rotary machine that empties the cylinders using pneumatic cylinders and passes them to a filling machine. Cylinders that fail to be emptied in the first cycle and that enter the machine at too low – pressure, are ejected at the pneumatic cylinder outlet conveyor. The machine effectively behaves as a kind of machine inspector, as this allows the high-pressure CO2 filling process to be repeated. The discharged CO2 is vented through the discharge valve and the venting duct by means of a fan. The process is described from the initial important design features to the electrical and software solution of the process
Development and implementation of a reward system in the intra-logistic system
No full textMagistrska naloga obravnava razvoj in implementacijo sistema nagrajevanja v logističnem okolju. Najprej predstavimo teoretično ozadje razpoznavanja govora in osnovne komponente sistema za razpoznavanje govora. Sledi pregled najnovejših trendov v intralogistiki s poudarkom na digitalizaciji. Opisana je integracija razpoznavalnika govora v intralogistične procese. V drugem delu magistrske naloge predstavimo uporabljene tehnologije, ki so osnova za implementacijo sistema nagrajevanja, ki ga v nadaljevanju tudi podrobno opišemo. Rešitev je prilagojena željam strank in se osredotoča na preglednost, prilagodljivost ter pripravljenost za prihodnje razširitve.The master\u27s thesis explores developing and implementing a reward system in a logistics environment. First, we present the theoretical background of speech recognition and the basic components of a speech recognition system. This is followed by an overview of the latest trends in intralogistics, emphasizing digitization. The integration of a speech recognizer into intralogistics processes is described. In the second part of the master\u27s thesis, we present the technologies used, which form the basis for implementing the reward system, which we also describe in detail. The solution is tailored to customers’ desires and focuses on transparency, adaptability, and readiness for future expansions
Armed robbery of Malalan jewellery store
No full textNekatera kazniva dejanja so ljudem nevidna, kar je tudi namen storilcev, premoženjska kriminaliteta, ki obsega med 70 in 80 odstotkov vse prijavljene in obravnavane kriminalitete, pa neposredno prizadene veliko ljudi. Premoženjska kriminaliteta zajema več kaznivih dejanj, med njimi izstopa kaznivo dejanje ropa, ki spada tudi med nasilna kazniva dejanja. Namen diplomskega dela je predstaviti značilnosti premoženjske kriminalitete in kaznivih dejanj ropov, predvsem oboroženih ropov, potek policijske preiskave in posebnosti pri preiskovanju tovrstnih kaznivih dejanj. Ker gre pri oboroženem ropu za osebni stik med storilcem in žrtvijo, ki na eni strani predstavlja osebne lastnosti storilca oziroma storilcev, na drugi strani pa prestrašeno žrtev, je treba pri obravnavanju tovrstnih dejanj poleg aktivnosti in ukrepov za ugotavljanje storilca posebno pozornost nameniti tudi delu z žrtvami. Storilčev namen je pridobiti protipravno premoženjsko korist, za kar je pripravljen uporabiti nasilje, zaradi česar se nekatera dejanja končajo tudi tragično. Tovrstna kazniva dejanja na območju Republike Slovenije izvršujejo izkušeni storilci ali člani kriminalnih združb, ki prihajajo tudi iz tujine. Na kazniva dejanja se zelo dobro pripravijo, izvršijo jih profesionalno in za seboj ne puščajo veliko sledi. Ena takih združb, poimenovana Pink Panter, prihaja z območja bivših jugoslovanskih republik, izvršuje pa tatvine dragih ur in izbranega nakita. Storilci ali člani kriminalnih združb so izjemno mobilni, organizirani, med seboj lojalni in običajno ne sodelujejo s policijo. Zaradi vseh teh okoliščin preiskovanje oboroženih ropov zahteva celovit pristop, ki vključuje sodelovanje z občani in več službami znotraj policije ter mednarodno policijsko in pravosodno sodelovanje.Some criminal offences are hidden from the public eye, which is also the intention of perpetrators. Property crime, which amounts to 70–80% of all reported and investigated criminal offences, directly affects many people. Property crime involves a number of criminal offences, with robbery, which belongs to violent criminal offences, at the forefront. The aim of this paper is to present characteristics of property crime and robberies, particularly armed robberies, the course of a police investigation and particularities of the investigation of such criminal offences. Due to a personal contact between a perpetrator and a victim in the event of an armed robbery, the paper presents the perpetrator(s) and their personal characteristics on the one hand and the terrified victim on the other. In addition to activities and measures used to identify the perpetrator in the investigation of such criminal offences, particular attention should be paid to working with victims as well. The aim of the perpetrator is to make an unlawful gain, and they do not hesitate to use violence, therefore some criminal offences end tragically. Such criminal offences in the area of the Republic of Slovenia are committed by perpetrators or members of criminal organisations, including from abroad. They prepare well for the criminal offences, and they commit them professionally, not leaving much trace. One such organisation named Pink Panther originates from former Yugoslav republics and steals expensive watches and fine jewellery. Perpetrators or members of criminal organisations are extremely mobile, organised, loyal to one another and usually do not cooperate with the police. Due to all these circumstances, the investigation of armed robberies requires a comprehensive
approach, including the cooperation with locals and a number of police services as well as international police and judicial cooperation
Overall equipment effectiveness in company OMCO Metals Slovenia
No full textVpeljava kazalnika OEE (celovita učinkovitost opreme) omogoča podjetju zaznavanje ključnih pomanjkljivosti v proizvodnjem procesu in posledično optimizacijo le-tega. V nalogi je najprej predstavljen kazalnik OEE in njegovo teoretično ozadje. Osrednji del naloge predstavlja analiza učinkovitosti opreme (proizvodne linije) v obravnavanem podjetju. Vse 3 postavljene hipoteze so izračuni potrdili, kar kaže na precejšenj potencial za izboljšave. Za konec so podani predlogi za nadaljno vpeljavo kazalnika in možne izboljšave procesa s ciljem optimizacije proizvodnje.Introduction of the OEE (Overall Equipment Effectiveness) indicator enables a company to detect key deficiencies in the production process and subsequently optimize it. The thesis first presents the OEE indicator and its theoretical background. The central part of the thesis presents an analysis of the effectiveness of equipment (production line) in the company under consideration. All three hypotheses were confirmed by the calculations, indicating significant potential for improvements. Finally, suggestions for further introduction of the indicator and possible process improvements are provided with the aim of optimizing production
