Iskanje po katalogu digitalne knjižnice

Opis: The support for an ongoing global pursuit of sustainable development, consumer awareness about sustainability, and regulations have affected the transport and logistics sector due to the fact that it presents ample environmental, social and economic challenges. The transport sector contributes globally to about 14% of greenhouse gas emissions, and around one third of the European Union's emissions, yet also represents an important economic sector, employing around 10 million individuals, thus requiring an in-depth discussion, especially regarding environmental impact. Due to increasing global concern for the environment, companies and policymakers are facing pressure to reduce the environmental impact related to transport and logistics activities and make them more sustainable. Before choosing a best practice for improvement, especially regarding the environmental perspective, a thorough analysis regarding the environmental impact has to be carried out based on reliable data and methodology. For such purposes, the life cycle assessment (LCA) defined by standards ISO 14040 and 14044 is commonly used. While the LCA focuses only on the environmental perspective, sustainability is represented by three dimensions, which are environmental, economic and social and those are interlinked, which presents a challenge, as each dimension has a major impact on every stage of the life cycle of a product, process or service. Thus there is a need to evaluate all three perspectives of sustainability in order to make transport and logistics processes more sustainable. Another option to make transport and logistics processes more sustainable and to achieve sustainable development is through education. Thus, it is important to integrate sustainability-oriented topics in logistics programs and courses, and consequently educate future logisticians about sustainability. Considering environmental burdens and sustainable development in transport and logistics, we explored LCA regarding its use in transport and logistics and studied the integration of sustainability into logistics education in EU, as it is important to educate future logistics managers and decision makers to gain sufficient knowledge on the importance of sustainability. Also, as logistics processes pose several environmental challenges and impacts, social and economic impacts are the ones that are frequently overlooked. Thus we additionally focused on performing an applicable comprehensive sustainability evaluation of a monkey toy and evaluated its environmental (through LCA), social (through SLCA) and economic (through LCC) impacts through the life cycle. At the same time, we explored options to enhance the present CE concept in the monkey toy company. Exploring the use of LCA in transport and logistics, we focused on the state-of-the-art of transport-related life cycle assessment studies, as they are important for the decision-making processes. Our research of LCA & transport studies was framed around the requirements of the International Organization for Standardization. A specific focus was given to the quality of life cycle assessment phases, comprehending goal and scope, inventory, life cycle impact assessment, and interpretation. Thirty-four research and review papers were studied, sourced from the Web of Science database. Studying the monkey toy, we firstly assessed the environmental impacts of the toy through LCA and additionally combined it with SLCA and LCC to evaluate the toy's sustainability comprehensively. Based on the results of the sustainability evaluation, we gained an insight into environmental, economic and social hotspots that the monkey represents. We then presented a possible enhancement of the CE concept. Lastly, focusing on logistics education, we analyzed and elaborated upon an integration of sustainability topics at higher education programs in logistics and their curricula for bachelor and master degrees at universities across Europe.
Ključne besede: Logistics, Transport, Sustainability, Life-cycle assessment, Logistics education
Objavljeno: 26.03.2021; Ogledov: 46; Prenosov: 0

Opis: In this thesis the classical and quantum dynamics in billiard systems are considered. Extensive numerical studies of the classical transport properties in several examples of billiard families including the ergodic Bunimovich stadium and cut-circle billiards and the mixed-type Robnik and lemon billiards are performed. The analysis of the transport is based on the random model of diffusion which assumes that due the strongly chaotic dynamics the motion of the orbit on the discretized phase space is temporally uncorrelated. The cause of the deviations from the random model dynamics is traced to dynamical trapping due to stickiness. A novel approach to locally quantifying stickiness based on the statistics of the recurrence times is presented and applied to distinguish between exponential decays of recurrence times and other types of decays. This enables the identification of sticky areas in the chaotic components. Detailed maps of their structure for a wide range of parameter values, mapping the evolution of the mixed-phase spaces and revealing some particularly interesting special examples are presented. The recurrence time distributions in sticky areas are found to be well described by a mixture of exponential decays. The transport of particle ensembles in the momentum space of classical billiards is described by using an inhomogeneous diffusion model and the classical transport times are determined. The classical transport times are vital for the analysis of the localization of chaotic eigenstates in quantum billiards. The control parameter that describes the the degree of localization of the chaotic quantum eigenstates is the ratio between the Heisenberg time (Planck's constant divided by the mean level spacing) and the classical transport time. Extensive numerical calculations of the high-lying spectra and eigenstates of the stadium, Robnik and lemon quantum billiards are performed. The spectral statistics are analysed in terms of the standard methods of quantum chaos. The level repulsion exponent of localized eigenstates is found to be a rational function of the control parameter. The degree of localization is determined with respect to localization measures based on the Poincaré-Husimi representation of the eigenstates. The mean localization measure is found to be a rational function of the control parameter and linearly related to the level repulsion exponent. The distributions of the localization measures are analysed and found to be of a universal shape well described by a two parameter empirical distribution in billiards with no apparent stickiness. The nonuniversal system specific features of localization measure distributions are related to the presence of sticky areas in the phase spaces of classical billiards with specific examples shown.
Ključne besede: Transport, localization, chaos, quantum chaos, Hamiltonian systems, level spacing distribution, mixed phase space, billiard, quantum billiard, Husimi functions, stickiness, cantorus, chaotic eigenstates, level repulsion.
Objavljeno: 13.01.2021; Ogledov: 194; Prenosov: 39
Celotno besedilo (24,93 MB)

Opis: Vsako podjetje, tudi Pošta Slovenije, potrebuje logistične storitve za zagotavljanje povezave med podjetjem in njegovim okoljem (dobavitelji, strankami ipd.). V interesu Pošte Slovenije je, da paletne pošiljke, kot tudi ostale pošiljke, odpravi do strank čim hitreje, kakovostno, varneje ter tudi najugodnejše predvsem s finančnega vidika. Palete nam pomagaju pri lažji manipulaciji z blagom in transportom blaga. Prevoz paletnih pošiljk naj bi bil varen in kakovosten, vendar to ni vedno tako, zaradi težav, ki se pojavljajo pri manipulaciji s paletnimi pošiljkami. Paleta je namensko izdelana lesena podloga, na katero zlagamo kosovni tovor (kartoni, vreče, zaboji ipd.) z namenom standardiziranja tovorne enote, s katerimi hitreje, varneje in stroškovno učinkoviteje opravljamo transport. Uveljavljajo se v vseh dejavnostih (proizvodnja, transport, distribucija ipd.), njihova množična uporaba pa močno vpliva na poenostavitev ter zmanjšanje stroškov v celotni logistični verigi. Namen diplomskega dela je predstaviti procese upravljanja s paletnimi pošiljkami in podati prednosti in slabosti teh procesov ter možne rešitve obstoječega stanja.
Ključne besede: Proces, logistika, transport, paletne pošiljke, manipulacija paletnih pošiljk
Objavljeno: 08.01.2021; Ogledov: 98; Prenosov: 18
Celotno besedilo (1,94 MB)

Opis: Dandanes se tako v logističnih kot v prevoznih podjetjih srečujejo s težavami, kako izbrati način dostave ali prevoz pošiljke. Podjetja poskušajo poslovati čim bolj ekonomično, zaradi česar se poslužujejo različnih načinov dostave oziroma prevoza svojih pošiljk s čim nižjimi stroški. Ker so lahko pošiljke zelo različne po obliki, dimenziji in masi, je zelo pomembno, kakšen način prevoza izberemo. Zaradi omenjenih raznolikosti ne poznamo univerzalnega pravila, ampak je vsakokrat potrebno analizirati in preveriti možnosti prevoza za optimalno končno dostavo. Poznamo dva načina, ki se najbolj uporabljata v velikih prevoznih podjetjih. Najenostavnejši je neposreden prevoz, ki je, kot že ime pove, neposreden od točke A do B, brez vmesnih postankov. Drugi način je prevoz po modelu »hub-and-spoke«. To je prevoz z večjim številom pošiljk hkrati. V tem modelu so t. i. »hub-i« vozlišča, v katerih se pošiljke zbirajo ter pripravijo na skupen prevoz in »spoke-i«, ki predstavljajo izhodiščne točke ali pa končne destinacije, v katere je pošiljka namenjena. V postopku izbire med dvema modeloma je na prvem mestu vedno želja stranke. Stranka lahko določi, na kakšen način želi, da je pošiljka prenesena. Če stranka določi le datum prevzema in dostave, se lahko sami odločamo, na kakšen način bo dostavljena. V podjetju analiziramo pošiljke. Z analizo preverimo dimenzije, maso ter izvirno in namembno mesto pošiljke. V diplomski nalogi smo raziskali težave in postopek izbire v logističnem podjetju Jöbstl. Opravili smo analizo izbire in učinkovitosti načina prevoza. Prav tako smo raziskali način, s katerim lahko izboljšamo postopek in prevoz. Podali smo predloge in rešitve za optimizacijo prevoznih modelov, s katerimi bi lahko izboljšali oskrbovalno verigo kot sam proces prevoza različnih pošiljk od pošiljatelja do prejemnika.
Ključne besede: neposreden transport, »hub-and-spoke«, pošiljka, zbirnik, skladišče.
Objavljeno: 23.10.2020; Ogledov: 134; Prenosov: 20
Celotno besedilo (1,85 MB)

Opis: V magistrski nalogi smo izdelali DEM analizo obrabe pločevine presipnega mesta tračnega transporterja z uporabo programa EDEM. V numerični analizi smo najprej določili geometrijo presipnega mesta, ki jo sestavljajo dohodni del tračnega transporterja, odhodni del tračnega transporterja, pogonski boben in presipno mesto. S pomočjo računalniško podprtega orodja EDEM smo izdelali numerično DEM analizo obrabe pločevine presipnega mesta, pri čemer smo spreminjali parametre oblike presipnega mesta, material (pločevine) presipnega mesta, hitrost transportiranih delcev in velikost masnega toka transportiranih delcev. Pri analizi obrabe pločevine presipnega mesta smo dobili ustrezne mere izbrane oblike presipnega mesta in ustrezno hitrost transportiranega materiala, ki nam prinaša najdaljšo življenjsko (obratovalno) dobo presipnega mesta. Izdelali smo tudi primerjavo obrabe pločevine presipnega mesta, ki nastane pri različnih masnih tokih transportiranih delcev, vlažnostih transportiranih delcev in materialnih lastnostih pločevine presipnega mesta. Vsi rezultati so tudi grafično prikazani.
Ključne besede: logistika, transport sipkega materiala, DEM analiza, analiza obrabe z uporabo programa EDEM
Objavljeno: 25.09.2020; Ogledov: 60; Prenosov: 14
Celotno besedilo (3,57 MB)