75,315 research outputs found
Age-depth models and dust-mass accumulation rates for loess-palaeosol sequences from the Carpathian Basin
No full textFigure 1 represents the Bacon.r age-depth models for the: a) Irig b) Nosak c) Stari Slankamen and d) Crvenka loess-palaeosol sequences while figure 2 shows the corresponding dust-mass accumulation rates (minimum, maximum, mean and median values) calculated according to the modeling results for the same sites. Appendix A contains the modeled ages for the Irig, Nosak Stari Slankamen and Crvenka loess-palaeosol sequences
Comparison of mitochondrial and nuclear genetic markers of Barrel jellyfish (Rhizostoma pulmo) from North Adriatic and central Mediterranean biogeographic region
No full textUgotavljal sem genetsko raznolikost v populacijah velikega klobučnjaka (Rhizostoma pulmo), ki so bili nabrani v Sredozemskem morju. Vzorci so bili nabrani v različnih biogeografskih regijah (severni Jadran, obala severne Afrike, zahodno Sredozemlje). V 65 vzorcih iz 8 vzorčnih mest sem analiziral nukleotidna zaporedja COI in regij ITS. Z reakcijo PCR sem pomnožil zapis za dva genetska markerja, ki sem jih nato uporabil za filogenetske analize..
An analysis of purchase resources and an upgrade of decision making process using a multi-criteria decision model in Ebm-papst company.
No full textV magistrskem delu obravnavamo analizo nabavnih virov in nadgrajujemo proces odločanja z uporabo večkriterijskega odločitvenega modela. V izbranem podjetju Ebm-papst so se zaradi vedno večje konkurenčnosti in v želji kreiranja nabavnih prihrankov lotili iskanja novih nabavnih virov na področju jugovzhodne Evrope za blagovno skupino aluminijastih odlitkov. Z analizo smo ugotovili, da imajo v podjetju definiran zgolj proces ocenjevanja obstoječih dobaviteljev, zato smo se lotili nadgradnje procesa izbora novega dobavitelja. V prvem koraku smo na podlagi pregleda strokovne literature empirično proučili ter izpostavili najpomembnejše kriterije pri izboru novega dobavitelja. Ti so bili izbrani na podlagi matrike SPM in PPM. Za pridobivanje podatkov smo uporabili kvantitativno in kvalitativno znanstvenoraziskovalno metodo. Analizo smo opravili na podlagi izpolnjenih vprašalnikov ter ocenjevanj, opravljenih med obiskom pri dobaviteljih. Opravljen pa je bil tudi nestrukturiran globinski intervju s petimi strokovnjaki, nabavniki aluminijastih odlitkov. Zaradi kompleksnosti smo problem odločanja razdelili na dve stopnji. V prvi stopnji smo definirali izločitvene kriterije in s t testom preverili hipotezi. Pripravili smo odločitveni model z uporabo metode DEX ter definirali štiri strategije pristopa do novih dobaviteljev pri vključevanju teh v panel dobaviteljev, kar bo imelo praktične implikacije za izbrano podjetje in širše. Opravili smo vrednotenje dvanajstih dobaviteljev ter na podlagi praktičnih testov ocenili razviti model ter predlagali tudi izboljšave, vezane na model. V zaključku smo podali predloge izboljšav za celoten proces izbora novih dobaviteljev v izbranem podjetju.In the master\u27s thesis, we discuss the analysis of procurement sources and we upgrade the decision-making process using a multi-criteria decision model. Due to increasing competitiveness and the desire to make purchasing savings, the selected company Ebm-papst started searching for new purchasing sources in the area of Southeast Europe for the aluminum castings product group. With the analysis, we found that the company has only defined the process of evaluating existing suppliers, so we proceeded to upgrade the selection process of a new supplier. In the first step, based on a review of the professional literature, we empirically examine and highlight the most important criteria in selecting a new supplier. These were selected based on the SPM and PPM matrix. For obtaining data, quantitative and qualitative research methods were used. The analysis was performed on the basis of completed questionnaires and assessments performed during a visit to suppliers. An unstructured in-depth interview was also conducted with five experts, purchasers of aluminum castings. Due to the complexity, we divided the decision-making problem into two stages. In the first stage, we defined the exclusion criteria and tested the hypotheses with a t-test. We prepared a decision model using the DEX method and defined four strategies of approach to new suppliers in the inclusion of the latter in the panel of the suppliers, which will have practical implications for the selected company and more. We evaluated twelve suppliers and, based on practical tests, we evaluated the developed model and we also proposed model-related improvements. In conclusion, we made suggestions for improvements for the entire process of selecting new suppliers in the selected company
Production of filament from polyvinyl alcohol and microcrystalline cellulose
No full textUporaba aditivnih tehnologij je v porastu. Ena izmed teh je tudi tehnologija ciljnega nalaganja. 3D tiskalniki, ki delujejo po principu ciljnega nalaganja, uporabljajo filamente iz različnih polimerov. Zaradi svetovnih razmer so v ospredju raziskav biorazgradljivi materiali. V nalogi obravnavamo izdelavo okolju prijaznega filamenta za 3D tiskalnik iz polivinil alkohola z dodatkom mikrokristalne celuloze za izboljšanje mehanskih lastnosti. Izdelali smo testne granule iz polivinil alkohola in mikrokristalne celuloze v različnih koncentracijah. S postopkom ekstruzije smo granule pretvorili v filamente z različnimi vsebnostmi celuloze. Na vzorcih filamentov smo opravili optične analize in dimenzijske meritve. Ugotovili smo, da so filamenti v večini homogeni in dobro strukturirani. Vendar so za uporabo filamenta na 3D tiskalniku še potrebne dodelave.The use of additive manufacturing technologies is on the rise. One of these is also Fused Filament Fabrication. 3D printers, that use FFF technology, use polymer filaments. Due to the global situation, biodegradable materials are at the forefront of research. The aim of the thesis is to make an environmentally friendly filament for 3D printers from polyvinyl alcohol with the addition of microcrystalline cellulose to improve mechanical properties. Test granules from polyvinyl alcohol and microcrystalline cellulose in different concentrations were transformed into filaments with different cellulose contents using extrusion process. Optical analyses and dimensional measurements were carried out on filament samples. We found out that filaments are mostly homogenous and well structured. But for use on a 3D printer out methodology needs some finishing
Construction of a tensile tester for light loads
No full textPri razvoju in izdelavi biorazgradljivih polimernih filamentov se pojavljajo problemi s premajhno trdnostjo in krhkostjo materiala. Vse izdelke je potrebno testirati, da se lahko optimira parametre izdelave. Kot podpora izdelavi biorazgradljivih materialov smo v sklopu dela zasnovali in izdelali manjšo napravo za natezni preizkus, ki bo na voljo pri izdelavi filamentov. Za osnovo je bila vzeta kovinska konstrukcija odslužene naprave za merjenje hrapavosti. Izdelali smo sistem za merjenje sile z merilno celico in raztezka s kamero. Izvedli smo natezne preizkuse na filamentih ter natisnjenih epruvetah in preverili ali sistem ustreza standardu ISO 527, ki določa pravila za merjenje nateznih lastnosti plastik.In the development and production of biodegradable polymer filaments, problems arise with insufficient strength and fragility of the material. All products must be tested in order to optimize the manufacturing parameters. To support the production of biodegradable materials, we have designed and produced a small device for tensile testing, which will be available during the production of filaments. The metal structure of roughness measuring device, which was no longer in use, was taken as the basis. We made a system for measuring force with a measuring cell and elongation with a camera. We performed tensile tests on filaments and printed tubes and checked whether the system complies with the ISO 527 standard, which defines the rules for measuring the tensile properties of plastics
The Benefits of Being Economics Professor A (and not Z)
No full textAlphabetic name ordering on multi-authored academic papers, which is the convention in the economics discipline and various other disciplines, is to the advantage of people whose last name initials are placed early in the alphabet. As it turns out, Professor A, who has been a first author more often than Professor Z, will have published more articles and experienced afaster growth rate over the course of her career as a result of reputation and visibility. Moreover, authors know that name ordering matters and indeed take ordering seriously: Several characteristics of an author group composition determine the decision to deviate from the default alphabetic name order to a significant extent.performance measurement, incentives, economists, name ordering
Final word on Jersey Dutch
No full textIn this article, William Z. Shetter compares and contrasts the dialects that developed between different Dutch colonies in the New World. He explores in-depth the nuances of Jersey Dutch, and provides theories to explain how Dutch and colonial languages blended. The article is reprinted from American Speech, December 1958, Volum XXXIII, No. 4
Logarithmic variance profiles and the corresponding f-1 spectra of temperature fluctuations in turbulent Rayleigh-Bénard convection
No full textWe report experimental results for the temperature variance 2(z) and the corresponding frequency spectra P(f) in turbulent Rayleigh-Bénard convection (RBC) in a cylindrical sample of aspect ratioT= D/L = 1:00 (D = 1:12 m is the diameter and L = 1:12 m the height). The measurements were conducted in the Rayleigh-number range 1011 < Ra < 1:35 1014 and Pr ' 0:8. For Ra = 1:35x1014, 2(z) could be described well by a logarithmic dependence on the vertical position z in a range of z 1 < z < z 2 with z 1 ' 70 and z 2 = 0:1L. Here L=(2Nu) is the thickness of a thin thermal sublayer adjacent to the horizontal plate where the heat flux (denoted by the Nusselt number Nu) is carried mostly by thermal diffusion. In the log layer, we found that the temperature spectra had a significant frequency range over which P(f) f with close to 1. As Ra decreased, increased so that the log layer became thinner. At Ra = 2:05 1011, z 2 < z 1 and therefore there was no range for a log layer. Correspondingly, the temperature spectrum near the horizontal plate did not have the f1 scaling form either
Statistics of the subgrid scales after the shock-turbulence interaction
No full textThe interaction of a normal shock with isotropic turbulence (IT) represents a basic problem for studying some of the phenomena associated with high speed flows, such as hypersonic flight, supersonic combustion and Inertial Confinement Fusion (ICF). In general, in practical applications, the shock width is much smaller than the turbulence scales and the upstream turbulent Mach number is modest. In this case, recent high resolution shock-resolved Direct Numerical Simulations (DNS) (Ryu and Livescu, J. Fluid Mech., 756, R1, 2014) show that the interaction can be described by the Linear Interaction Approximation (LIA). By using LIA to alleviate the need to solve the shock, DNS post-shock data can be generated at much higher Reynolds numbers than previously possible. Here, such results with Taylor Reynolds number around are used to investigate the properties of the subgrid scales (SGS). In particular, it is shown that the shock interaction decreases the asymmetry of the SGS dissipation PDF as the shock Mach number increases, with a significant enhancement in size of the regions and magnitude of backscatter
Transition to turbulence in a qblique shock-wave/boundary-layer interaction at M=15
No full textDirect numerical simulations are carried out for different forcing techniques to trigger transition during the interaction between an oblique shock-wave and a laminar boundary-layer at M = 1.5. Three forcing methods are used: a) forcing of oblique unstable modes, whose shape and behaviour are determined by the local linear stability theory, b) broadband free-stream acoustic disturbances, and c) a cold plasma flow control device. While the oblique-mode breakdown is dominant for low-amplitude forcing, long streaky structures drive the transition process in a high-amplitude disturbance environment. LES are also performed on the experimental setup by the Institute of Theoretical and Applied Mechanics (ITAM) from Novosibirsk State University with cold plasma actuation. As well as the disturbance type, the effect of Reynolds number and forcing amplitude will be investigated
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