A multi-objective mathematical programming for sustainable reverse logistics network design. Part II: Model application and analysis

Source at https://www.witpress.com/books/978-1-78466-169-4. Reverse logistics has received more and more attention during the past decade due to the increasing public awareness of sustainable development. Because of the fluctuation in both quantity and quality of the reverse material flow, design and planning of reverse logistics network is much more complicated compared with the forward ones. Therefore, it is important to develop decision support tools for designing reverse logistics network in an economically efficient and environmental-friendly manner. This research proposes a novel multi-objective mixed integer programming model in order to justify the relationship between the cost and sustainability of reverse logistics system, and the weighted sum utility method is employed for combining the two objective functions. This research is presented in a series of two papers. Part I formulates the conceptual framework of reverse logistics network and the mathematical programming for the minimization of the overall system cost and environmental influence. Part II introduces the weighted sum utility method for combining the two objective functions, and the application and analysis are also given in this part

High-resolution heavy mineral studies on “black sands” from the Nama Group (Fish River Subgroup) in Namibia – Part II.

Master's thesis in Petroleum Geosciences Engineering“Black sands” from a presumed heavy mineral placer of the Nama Group in Namibia will be studied in detail. The samples for this thesis are collected from various outcrops belonging to the Fish River Subgroup in the Nababis Formation. This formation lies in the Nama Basin, in which the Haribes Member is deposited. High-resolution heavy mineral stratigraphy for the succession will be used to determine provenance of the detrital material. To achieve this, a methodical approach will be used where geochemistry, XRD (X-Ray Diffraction), and semi-quantification of heavy minerals using MLA (Mineral Liberation Analyzer) are combined with FEG-SEM-BSE-EDS-CL (Field Emission Gun Scanning Electron Microscope, Back Scattered Electron, Energy Dispersive Spectrometer and Cathodoluminescence). Heavy mineral size distribution suggests normal size distribution with peaks around 125-150 microns for all samples, with one exception, Zf 409, which has bimodal size distribution in the range of 75 – 125 microns. Furthermore, all heavy mineral particles are generally angular to sub-angular, which can infer a short transportation route. The samples display relative similar mineralogy according to FEG-SEM and MLA analyses. One can suggest a proximal metamorphic source based on findings of i.e. chamosite, garnets, clinopyroxene, as well as the possibility of the identified grossular are Ca-epidotes according to XRD analysis. Moreover, the chemical composition of garnets was plotted in ternary diagrams, which show evidence of amphibolite facies and metabasic rock associations. Provenance studies can be very useful to determine the tectonic setting of the sedimentary successions and the detrital material. By determining the main characteristics of the depositional basins and the source areas of the deposited detritus, it is possible to understand sedimentological processes. This is one of the important sources of information for the mineral and petroleum industry that need to evaluate potential plays

Escalation in asymmetrical relations. A rational strategy for weak states?

It is a prevalent view in International Relations scholarship that in conflicts the most powerful party generally prevails. It would follow that weak party escalation usually is an irrational course of action, and therefore should not be attempted. Nonetheless, comparably weak states from time to time escalate confrontations with vastly stronger adversaries, and benefit from it. This paradox is not well understood. While there is a large literature on escalation, it is primarily concerned with situations of symmetrical power. A rare exception is Angstrom and Petersson (2019), who propose that weak party escalation can be rational given specific conditions of the weak state’s preferences, capabilities, or alliances. Asymmetrical conflicts and confrontations of various intensity are numerous, and taking place in politically important regions such as the South China Sea, the Middle East, Eastern Europe, and the Arctic. This paper addresses the knowledge gap surrounding the repeatedly observed, though scarcely understood, phenomenon of weak party escalation. Grounded in offensive realism and theory on strategy of conflict, I aim to answer the research question: how can weak parties in asymmetrical relations use escalation to advance their strategic interests?. Using game theoretical modelling and a case study of the Russo-Norwegian conflict of interest, this paper develops a rigorous explanation for successful weak party escalation. I argue that weak party escalation can be successful given specific conditions of the conflict, such as private information about the cost of conflict, the weak party being supported by a great power ally, or by the weak adopting a limited aims strategy

Aerodynamically Induced Yaw Behaviour for Floating Wind Turbines

The demand for more renewable energy grows stronger by the day. The world is experiencing more pollution and environmental damages from human activity than ever before. One of the possible solutions to produce more sustainable energy is offshore wind energy, more specifically floating wind energy. When transferring wind turbines to the sea, far from shore, they will be less intrusive on society as well as the wind is stronger and more constant. This thesis dives deeper into the aerodynamically induced yaw motion of a wind turbine floater. It also attempts to explain the underlying physics based on wind direction, wind speed and yaw stiffness provided by the mooring lines. To describe the fundamental mechanics, a static yaw system based on wind directions and rotor plane-angle for a wind turbine floater is presented. To find the combination of wind directions and -speed that causes large yaw rotations, numerical time-domain simulations are conducted in SIMA. A model of the INO WINDMOOR 12 MW turbine, using a semi-submersible floater is used in the study. This floating wind turbine is subjected to constant wind intensity with varying wind speeds and wind directions. This numerical study consists of two approaches: one analysis with a rotating floater, where platform yaw has been the output parameter, and one analysis fixing the floater and calculating the platform yaw moment based on internal forces. The internal forces are generated by the thrustforce acting on the turbine. Platform rotation and platform yaw moment is then matched and compared by using a non-linear mooring stiffness curve. From the simulations it was observed a quite good correlation for the platform yaw between the two analysis for wind speeds in the operational domain (0-25 m/s). For wind speeds above 25 m/s, in the idling phase, a larger deviance was observed. The rotating floater experienced large rotations for some wind directions when subjected to an extreme case of 45 m/s. The fixed floater on the other hand, was unable to capture this self-reinforcing unstable yaw effect, which was observed for the rotating floater

From identity politics to dismodernism? Changes in the social meaning of disability art

Art has gained an important position in the identity politics of the disability movement. The article sheds light on how disabled artists enact their positions as disabled and as artists. In a qualitative survey, a total of 30 artists affiliated with the disability arts movement in the United Kingdom and United States were interviewed. Most believe that disability art has developed in two phases. The first phase is closely related to the emerging disability rights movement in the late 1970s and early 1980s. The idea of the present situation as a second phase of disability art is characterized by artists wanting to perform and to exhibit for a mainstream audience, and by a combination of disability issues and non-disability issues. These changes in the social field of disability art seem to be structured by the disputed identity politics of the disability movement

For mulighet til deltakelse (?) : en kritisk analyse av faglige/vitenskapelige og politiske diskurser rundt presbyacusis og livskvalitet

Bakgrunn for problemstilling Gruppen eldre blir stadig større, noe som tilsier at antall mennesker med aldersrelatert hørselshemning (presbyacusis) også øker. Dette faktum aktualiserer en debatt rundt presbyacusis og livskvalitet. Grunntanken i denne oppgaven er at det er viktig å forstå hvilke diskurser som råder rundt de eldre med nedsatt hørsel for å forstå bedre hvordan en best kan hjelpe de som opplever hørselstapet som kilde til redusert livskvalitet. Med dette som utgangspunkt, er problemstillingen formulert som følger: Hvilke likheter og forskjeller finner man i de faglige/vitenskapelige diskursene og de politiske diskursene rundt aldersrelatert hørselshemning og livskvalitet? Underrettet dette, ligger spørsmålet om hvilke diskurser som råder innen de ulike feltene, og om de kan ses på som begrensende og patologiskapende eller frigjørende og myndiggjørende? Tittelen ”For mulighet til deltakelse (?)” viser hovedsakelig til oppgavens hensikt, altså å bidra til en kunnskapsutvikling som kan bedre presbyacusisrammedes muligheter til et liv med mindre isolasjon og ensomhet. Et liv med bedre livskvalitet. Spørsmålstegnet representerer oppgavens drøfting rundt hvordan dette formålet fremkommer og tas hensyn til i to statlige dokumenter som blir analysert. Metode og materiale I tråd med problemformuleringen er Faircloughs kritiske diskursanalyse valgt som metodisk innfallsvinkel i denne kvalitative, teoretiske masteroppgaven. Hans tredimensjonale modell danner en struktur i analysen, hvor to statlige dokumenter gjennomgås og settes opp mot faglige/vitenskapelige diskurser presentert tidligere i teorikapittelet. Det hele ses til slutt i forhold til strømninger i det audiopedagogiske fagfeltet. Formålet er å dekonstruere de strukturer som utgjør ens ”naturlige” omverden, et forsøk på å vise at den gitte forståelse av verden er et resultat av politiske prosesser med sosiale konsekvenser. Resultater og konklusjoner Oppgaven resulterer ikke i en endelig konklusjon. Det har snarere vært et ønske å synliggjøre kompleksiteten i diskursene rundt presbyacusis og livskvalitet. I tråd med Faircloughs fokus på makt, ser en derimot også her at de ulike diskursene står i hegemoniske forhold til hverandre, noe som kan sies å understreke viktigheten av et fokus på diskurs som en form for sosial praksis som avspeiler og er med på å forsterke ulike maktrelasjoner

Performance of molybdenum disulfide as anode material in lithium-ion

Målet med denne avhandlingen var å forberede og karakterisere det naturlige mineralet molybden disulfid fra den lokale gruven Knaben Gruver, for bruk som anodemateriale i litium-ion-batterier. Prosessen med å rense med svovelsyre, kulemølling og sikting produserte partiklene til størrelser under 45 mikrometer og ga få urenheter, materialet ble karakterisert ved testing som anode i en myntcelle. Det ble laget fire elektroder som ble satt sammen i myntceller med litium som mot- elektrode, to med et belegg av MoS2 på 60 mikrometer tykkelse og to med et belegg på 30 mikrometer tykkelse. To celler, en av hver beleggtykkelse, ble testet mellom 0,2 VLi og 3 VLi, og to ble testet mellom 0,9 VLi og 3 VLi. Cellene som ble utladet til 0,2 VLi viste tegn til tap av aktivt materiale og økning i ionisk motstand på grunn av den reversible reaksjonen mellom MoS2 og litium som løser seg opp i Mo og Li2S under 0,6 VLi. Cellene viser en høyere kapasitet, over 700 mAh g−1, i den initielle litieringen ved C/10 enn den teoretiske kapasiteten, 669 mAh g−1, på grunn av dannelse av SEI-laget. Kapasiteten reduseres imidlertid raskt ved sykling ved C/2. De tykkere elektrodene viser raskere nedbrytning, sannsynligvis på grunn av flere sidereaksjoner i cellen, og SEM-bildene viser mer sprekking av materialet i de tykkere cellene. Ved sykling av to celler mellom 0,9 VLi og 3 VLi ble kapasiteten i cellen redusert, siden den eneste reaksjonen som gir kapasitet er litium innterkalering i MoS2-lagene, denne reaksjonen gir bare 167 mAh g−1, mens dannelse av SEI-laget gir litt mer kapasitet enn teoretisk. Den tynnere elektroden viste ingen tegn til tap av aktivt materiale eller økning i ionisk motstand etter første syklus, og mindre sprekking ble observert i SEM-bildene etter sykling. MoS2 kan være et godt anodemateriale for litium batterier, men det kreves mer forskning for å forstå mekanismene ved litiering og delitiering. Ovenfra og ned tilnærmingen med kulemølling og testing av materialet gir en kapasitet som er nær den teoretiske ved lengre ladetider, men den raske nedbrytningen av cellen krever ytterligere forbedringer for å være egnet for kommersiell bruk