Underground Water Flow betwen Bloke Plateau and Cerknica Polje and Hydrologic Function of Križna Jama, Slovenia

Križna jama and Križna jama 2 are of important natural value. They have been known for more than hundred years from spe­leobiological, paleontological, geomorphological and touristic points of view. In 2007 the establishment of a water treatment plant on Bloke plateau raised important question: can partly cleaned water from the water treatment plant contaminate both caves and decrease their value? To answer this question a tracer test was carried out at the Bloke plateau. It showed gen­eral underground water flow from Farovščica ponor at Bloke plateau toward the Šteberščica spring at Cerknica polje. Mi­nority of recovered tracer appeared at Žerovniščica and Izvir v Podložu springs. The tracer was not detected at Studenec v Ložu and Zlatovec springs. Between ponor and springs three karst caves were observed. The highest concentration of tracer was detected in the cave Mrzla jama pri Bločicah and a much smaller concentration in the Križna jama and Križna jama 2. This shows that at middle water level the underground Farovščica stream does not flow directly through Križna jama and Križna jama 2 but near or below them. Since the tracer ap­peared in both caves only after the precipitation, underground water course can be significantly different at high water level. Tracing test also showed some characteristics of underground water flow through dolomite and characteristics of a composed aquifer with alogenic-autogenic recharge

Influence of solution hardening on microstructure and mechanical properties of Al-2.5Mg-0.7Li alloy

Although utilization of lightweight aluminum alloys in transportation industry reduced harmful emissions and improves fuel economy, their further application is limited by low stiffness, low Young modulus and sensitivity to elevated temperatures. It was found that specific strength properties of aluminum alloys can be improved by Li additions. The beneficial effect is achieved by precipitation of hardening Al3Li precipitate. The microstructural and mechanical properties of Al-2.5 Mg-0.7 Li alloy were investigated in as cast and solution hardened condition. The microstructure constituents and thermo-mechanical properties for both conditions were determined and compared

Analysis of the low energy layering fracture in Al- 2.5Mg-0.7Li alloy

The mechanism of nucleation and propagation of low energy layering fracture, observed during thermo-mechanical testing of Al-2.5Mg-0.7Li alloy in as cast condition, was analyzed. Since the low energy layering fracture is affected by Li segregations and microstructural constituents’ development, solidification sequence of Al-2.5Mg- 0.7Li alloy was investigated in equilibrium and non-equilibrium conditions. Results of the investigations have shown that Mg has more pronounced effect on low energy layering fracture due to reducing solubility of Li in liquid phase and αAl, maximizing precipitation of hardening (Al3Li) δ’ phase, ternary (Al2LiMg) T phase and (Al8Mg5) β phase, and reducing ductility by solid solution hardening

The Influence of Foundry Scrap Returns on Chemical Composition and Microstructure Development of AlSi9Cu3 Alloy

Recycling is now, more than ever, an important part of any foundry process due to the high cost of energy. The basis of the work presented here is a study of the addition of foundry scrap returns to the melt in order to reduce material and energy costs. The most important issue in such a process is the quality of both the prepared melt and final product. In this work, scrap returns were added to the AlSi9Cu3 base alloy in different proportions. Chemical composition was monitored, the solidification path was predicted by CALPHAD calculations and monitored by thermal analysis, and the formed microstructure was studied. The mechanical properties were also determined. The results showed that as the amount of scrap returns increased, elements such as Fe, Ni, Pb, Sr, etc. were more built up and elements such as Mg, Mn, Cr, etc. were decreased due to oxidation. The different chemical composition led to a reduced Mn:Fe ratio, resulting in the formation of needle-like Fe-rich phases and a decrease in mechanical properties

HOW WORK CONDITIONS INFLUENCE ON LEADERSHIP STYLES

Vsaka organizacija si zastavlja vprašanjekako voditi svoje zaposlene? Zaradi hitro spreminjajočega okolja je na to vprašanje včasih težko odgovoriti, težko je opredeliti katero tehniko je potrebno uporabiti, da bodo zaposleni v organizaciji zadovoljni in se počutili kot, da so del organizacije v kateri delujejo. Skozi čas je bilo sprejetih in implementiranih več stilov vodenja, nekateri so bili bolj uspešni od drugih, kar pa je zastavilo vprašanje kateri stil je najbolj primeren glede na situacijo v kateri je organizacija. Uspešnost vodenja pa je odvisna tudi od osebe, ki jo izvaja ter predanost zaposlenih do svoje vodje in organizacije. Strokovnjaki tega področja so prišli do enotnega mnenja, da najboljši stil vodenja ne obstaja. Uspešen vodja bo uporabil več stilov vodenja hkrati. Vodenje pa se ni možno naučiti iz knjig, znanje o vodenju prodobivamo z časom in izkušnjami.Every organization raises the questionhow to lead its employees? Due to the fast changing of the environment, it is sometimes hard to answer this question. It is hard to define which technique is necessary, to satisfy its employees so they feel like they are part of the organization. Through time there were many management styles that were accepted and implemented, some of them were more successful then the others, which raised the issue which management style is more appropriate, depending on the situation of the organization. The success of management is depending of the person that is implementing it, and the dedication of its employees. Experts in this field came to the conclusion that the best management style dosent exist. A successful leader will implement more then one management style at the same time. Leading can not be learned from books, knowledge will be obtained with time and experience

Purchase of printing paper by means of container transport

Magistrsko delo obravnava temo nabave tiskarskega papirja s pomočjo kontejnerskega transporta. V samemu začetku smo navedli cilje, namene, hipoteze, predpostavke in omejitve ter metode raziskovanja, ki smo jih uporabili za pisanje. Delo je sestavljeno iz štirih glavnih poglavji, ki obravnavajo teorije kontejnerizacije, tehnologijo kontejnerskega transporta, kontejnerske terminale in sam proces nabave tiskarskega papirja s pomočjo kontejnerskega transporta. V omenjenih poglavjih naloga podrobneje predstavi kontejnerizacijo in njen razvoj skozi zgodovino. Naloga se osredotoča tudi na vrste in standarde kontejnerjev ter njihov transport s pomočjo različnih transportnih sredstev. Naloga govori tudi o tehnologijah kontejnerskega transporta in elementih ter nalogah celinskega in pomorskega terminala. V samem koncu naloge bo predstavljen proces nabave tiskarskega papirja, kjer bodo obravnavane različne nabavne možnosti ter transportne metode. Na praktičnem primeru bo prikazan transport, varovanje in manipulacija tovora. Z realnimi cenami bo tudi prikazana in obrazložena najprimernejša nabava in transportna metoda tiskarskega papirja na mednarodnem trgu.The master\u27s thesis deals with the topic of procurement of printing paper by means of container transport. At the outset, we outlined the goals, purposes, hypotheses, assumptions, limitations, and research methods we used to write the thesis. The work consists of four main chapters dealing with containerization theories, container transport technology, container terminals, and the process of procuring printing paper through container shipping. In the mentioned chapters, the paper presents in more detail containerization and its development throughout history. The task also focuses on the types and standards of containers and their transportation through various means of transport. The task also discusses container transport technologies and the elements and tasks of both the inland and maritime terminals. At the very end of the assignment, the process of purchasing printing paper will be presented, which will discuss different purchasing options and transportation methods. In a practical example, the transport, protection, and handling of cargo will be shown. Real prices will also show and explain the most appropriate procurement and shipping method of printing paper in the international market

Vpliv dodatkov AlTi5B1 in AlSr10 na livnost zlitine AlSi9Cu3

This work studies the effect of the AlTi5B1 and AlSr10 additions on the fluidity and the solidification time of the AlSi9Cu3 casting alloy. The fluidity was investigated by determining the flow length in a spiral-shaped mould. The solidification time was measured with a thermocouple positioned at the ingate bottom. An individual pouring into the preheated (200 °C) metallic mould was done at different pouring temperatures ((640, 670, 700, and 710) °C). In all the cases, the fluidity was improved with the increasing pouring temperatures. An addition of the AlTi5B1grain refiner to the basic alloy reduced both the grain size and the fluidity, whilst the solidification time was similar to that of the basic alloy. On the other hand, an addition of the AlSr10 modifier refined the ßSi eutectic phase, increased the fluidity and prolonged the solidification time in comparison to the basic alloy. The fluidity was proportional to the solidification time. Thus, by carrying out a simple thermal analysis and determining the solidification time, it is possible to predict the fluidity.V delu je predstavljen vpliv dodatkov AlTi5B1 in AlSr10 na livnost in strjevalni čas livne aluminijeve zlitine AlSi9Cu3. Livnost smo preiskovali z merjenjem dolžine toka taline v kovinski kokili s spiralno livno votlino, medtem ko smo strjevalni čas merili s termoelementom, ki je bil vstavljen na dnu lijaka. Talino smo pri različnih livnih temperaturah ((640, 670, 700 in 710) °C) ulivali v predgreto kokilo (200 °C). Livnost je v vseh primerih naraščala z naraščanjem livne temperature. Dodatek udrobnilnega sredstva AlTi5B1 k osnovni zlitini je zmanjšal tako velikost kristalnih zrn kot livnost, medtem ko je bil strjevalni čas podoben kot v osnovni zlitini. Dodatek modifikatorja AlSr10 je zmanj{al velikost evtektične faze ßSi, povečal livnost ter podaljšal strjevalni čas v primerjavi z osnovno zlitino. Livnost je bila sorazmerna strjevalnemu času, tako da lahko z enostavno termično analizo in določanjem strjevalnega časa napovemo livnost preiskovane zlitine.V delu je predstavljen vpliv dodatkov AlTi5B1 in AlSr10 na livnost in strjevalni čas livne aluminijeve zlitine AlSi9Cu3. Livnost smo preiskovali z merjenjem dolžine toka taline v kovinski kokili s spiralno livno votlino, medtem ko smo strjevalni čas merili s termoelementom, ki je bil vstavljen na dnu lijaka. Talino smo pri različnih livnih temperaturah ((640, 670, 700 in 710) °C) ulivali v predgreto kokilo (200 °C). Livnost je v vseh primerih naraščala z naraščanjem livne temperature. Dodatek udrobnilnega sredstva AlTi5B1 k osnovni zlitini je zmanjšal tako velikost kristalnih zrn kot livnost, medtem ko je bil strjevalni čas podoben kot v osnovni zlitini. Dodatek modifikatorja AlSr10 je zmanjšal velikost evtektične faze βSi, povečal livnost ter podaljšal strjevalni čas v primerjavi z osnovno zlitino. Livnost je bila sorazmerna strjevalnemu času, tako da lahko z enostavno termično analizo in določanjem strjevalnega časa napovemo livnost preiskovane zlitine

The influence of cooling rate on microstructure and mechanical properties of AlSi9Cu3

The aim of this study was to determine the correlation between the size and the distribution of microstructural constituents and their cooling rate, as well as the correlation between the mechanical properties and the cooling rate of AlSi9Cu3 aluminum alloy when cast in high-pressure die casting (HPDC) conditions. In other words, the ultimate goal of the research was to determine the mechanical properties for a casting at different cooling rates. Castings with different wall thicknesses were chosen, and different cooling rates were assumed for each one. Castings from industrial technological practice were systematically chosen, and probes were extracted from those castings for the characterization of their mechanical properties. Special non-standard cylinders were created on which compressive tests were carried out. The uniqueness of this research lies in the fact that the diameters of the designed cylinders were in direct correlation to the actual wall thickness of the castings. This is important because the solidification of metal in the die cavity is complex, in that the cooling rates are higher on the surface of the casting than in the center. Local in-casting cooling rates were determined using numerical simulations. It was discovered that with increasing cooling rates from 60 K/s to 125 K/s the values for strength at 5% deformation increased on average from 261 MPa to 335 MPa