No description available.

No description available.

The implications of comminution practices on the planning of a typical open pit mine was investigated in this study by means of computer simulation. The objective was to assess the effects of mining costs as well as processing costs on the production plan of a typical open pit mine. For the purpose of the research, MineLib, an open library of ore body models was consulted. This led to the selection of a copper-gold ore body named “Newman1” for use in the strategic mine optimisation. Various scenarios were considered in order to highlight the contribution of comminution costs to the mine plan. In all the simulated scenarios, the objective function was to maximise the Net Present Value (NPV). And in terms of simulation setup, the comminution costs and cut-off grades were systematically varied from 70 % to 140 %. It was hence possible to investigate their effects on the NPV of the Newman1 ore body using SimSched, a freeware for mine optimisation and planning. Results showed that there is a great opportunity to increase the NPV of the Newman1 block model by adjusting the contribution of processing costs in general and comminution costs in particular. This can be achieved for instance by controlling the policy of cut-off grades, lowering production costs, and increasing throughput. / Civil and Chemical Engineering / M. Tech. (Chemical Engineering)

Idag pågår en diskussion om huruvida en typ av konsumenter exkluderas i modeindustrin och möjligheterna kring att få en bredare inkludering av större storlekar och varierande kroppstyper i modebranschen. Tidigare studier som har utförts på kvinnor med större storlek visar att det finns stora svårigheter att kunna visa upp och vara sitt sanna jag när det normativa modet och samhället inte tillåter det. Syftet med denna studie är att undersöka vilka praktiker som upplevs vara exkluderande och hur dessa hanteras. Forskningsfrågorna är: Vilka praktiker uppfattas som exkluderande av konsumenter?, och Hur hanterar konsumenten de identifierade exkluderingspraktikerna? Studiens teoretiska ramverk är baserat på begreppen exkludering, rutin och shopping som praktik från praktikteorin. Denna studie grundar sig i en kvalitativ forskningsmetod med en insamling av semistruktuerade intervjuer vilka är centrala för att fylla studiens syfte. Urvalet består av 10 kvinnor med storlekarna 44-54 i åldrarna 21-55, som ger en övergripande bild av olika upplevelser. Resultatet utgår från en matris som identifierar exkluderingspraktiker inom 4 olika teman som upplevs av konsumenten: (1) fysisk butik, (2) utbud & sortiment, (3) kategorisering och (4) marknadsföring. Resultatet visar att samtliga respondenter har upplevt storleksexkludering och hanterar det främst genom att bojkotta företag som exkluderar och handlar online. De likheter diskussionen fastställer mellan tidigare forskning och denna studie är att större storlekar har ett begränsat utbud och att designen skiljer sig från ordinarie sortiment. En exkluderingspraktik som tidigare studier inte har uppmärksammat är att konsumenterna med större storlekar har begränsade möjligheter till att vara hållbara konsumenter. Avslutningsvis bidrar studien med en sammanställning av tidigare forskning samt tillämpning av nya infallsvinklar. Den bidrar med förståelse till vilka praktiker konsumenten upplever som exkluderande och hur företagen påverkas av det. Samt vetskap om att det finns en köpstark och outnyttjad konsumentgrupp. De begränsningar som studien innefattar är att den yngre och äldre målgruppen inte undersöks, samt att studien enbart utgår från den kvinnliga marknaden. Eftersom denna studie undersöker den kvinnliga modemarknaden i åldrarna 20-55 år, är förslag för vidare forskning att studera den manliga modemarknaden för att bidra till en förändrad och mer inkluderande modeindustri för fler människor. / Today, there is a discussion about whether one type of consumer is excluded in the fashion industry and the possibilities of getting a broader inclusion of larger sizes and varying body types in the fashion industry. Previous studies that have been conducted on women of larger sizes show that there are great difficulties in being able to be their true selves when normative fashion and society do not allow it. The purpose of this study is to investigate which practices are perceived to be exclusive and how these are handled. The research questions are: Which practices are perceived as excluding consumers?, and How does the consumer handle the identified exclusion practices? The study's theoretical framework is based on the concepts of exclusion, routine and shopping as practice from the practice theory. This study is based on a qualitative research method with a collection of semi-structured interviews which are central to fulfilling the purpose of the study. The selection consists of 10 women with sizes 44-54 aged 21-55, which gives an overview of different experiences. The result is based on a matrix that identifies exclusionary practices within 4 different themes experienced by the consumer: (1) physical store, (2) supply & assortment, (3) categorization and (4) marketing. The results show that all respondents have experienced size exclusion and deal with it mainly by boycotting companies that exclude and shop online. The similarities the discussion establishes between previous research and this study are that larger sizes have a limited range and that the design differs from the regular assortment. An exclusionary practice that previous studies have not noticed is that consumers with larger sizes have limited opportunities to be sustainable consumers. Finally, the study contributes with a compilation of previous research and the application of new approaches. It contributes to an understanding of which practices the consumer perceives as exclusive and how companies are affected by it. As well as knowledge that there is a strong and unreached consumer group. The limitations which the study includes are that the younger and older target group is not examined, and that the study is only based on the female market. As this study examines the female fashion market between the ages of 20-55, the proposal for further research is to study the male fashion market to contribute to a changing and more inclusive fashion industry for more people.

Background: Larger dishware sizes have been shown to increase food portion sizes served and consumed by adults and children. Less is known about whether dishware size and design influences the amount of food caregivers serve to children. Whether smaller portion design plates can be used to help parents serve age-appropriate portion sizes to their children is unknown. This research is the first to examine the effects of dishware size and design on portion sizes served by caregivers. Methods: A within-subjects quasi-experimental design was used to determine the effects of dishware size and design on the portion sizes served by low-income caregivers to their preschool aged children during a buffet style meal. Three plate conditions were compared: a portion design plate, a plain child size plate, and an adult size plate. We hypothesized that when using the portion design plate, caregivers would serve the smallest amount of food compared to when using either the plain child size plate or the adult size plate. The amount of food served by caregivers to children was assessed using weighted methods. Results: The total amount of food (g) and energy (kcal) served did not differ across dishware conditions. Conclusions: Dishware size and design did not influence portion sizes served by caregivers. Additional factors may affect caregiver serving behaviors. / Epidemiology

Yes / The tribological performance of the piston assembly of an automotive engine is highly influenced by the complex flow mechanisms that supply lubricant to the upper piston rings. As well as affecting friction and wear, the oil consumption and emissions of the engine are strongly influenced by these mechanisms. There is a significant body of work that seeks to model these flows effectively. However, these models are not able to fully describe the flow of lubricant through the piston assembly. Some experimental studies indicate that droplets of lubricant carried in the gas flows through the piston assembly may account for some of this. This work describes an investigation into the nature of lubricant misting in a fired gasoline engine. Previous work in a laboratory simulator showed that the tendency of a lubricant to form mist is dependent on the viscosity of the lubricant and the type and concentration of viscosity modifier. The higher surface area-to-volume ratio of the lubricant if more droplets are formed or if the droplets are smaller is hypothesised to increase the degradation rate of the lubricant. The key work in the investigation was to measure the size distribution of the droplets in the crankcase of a fired gasoline engine. Droplets were extracted from the crankcase and passed through a laser diffraction particle sizer. Three characteristic droplet size ranges were observed: Spray sized (250–1000 μm); Major mist (30–250 μm); and Minor mist (0.1–30 μm). Higher base oil viscosity tended to reduce the proportion of mist-sized droplets. The viscoelasticity contributed by a polymeric viscosity modifier reduced the proportion of mist droplets, especially at high load.

No description available.

Master of Science / Department of Grain Science and Industry / Keith C. Behnke / The effect of tracer particle size on the accuracy of measuring retention time inside the conditioner of a pellet mill was studied. Three experiments were conducted using tracers with different particle sizes. The control retention time was calculated using the hold-up capacity method, while retention times for treatments were calculated using the pulse-input method. In addition to the previously prepared tracers, crystalline salt and powder color dye were used as tracers in this study to represent small particle tracers. In experiment one, large, medium, and small tracers were used. The treatment with large particle size was closer to the control with differences around 1.5%. Conversely, using the tracer with small particle size resulted in larger differences, approximately 18%. Two tracers were used in experiment two, resulted in 33% difference between treatment and control using a small particle size tracer, and a 10% difference using a tracer with similar particle size to the main materials. A tracer similar in particle size to the materials flowing inside the conditioner was used in the third experiment in addition to the salt and dye. Statistical analyses for this experiment indicated that particle size affects the accuracy of retention time measurements. There was a significant difference (P<0.05) in the comparison between salt and red color dye in treatment two, while there was no significant difference (P>0.05) between them in treatment one (same particle size). Moreover, in another comparison of the differences between treatments and their related controls, there was significant difference (P<0.05). However, the P-value for the red dye comparison (0.0126) was higher than that of salt (0.0026), which adds density as another influential factor that affects retention time measurement.

Considerable variation exists both within and between species in nuclear DNA content. Despite there being no obvious functional role for much of this DNA, many studies have reported phenotypic correlations with genome size at various taxonomic levels. This suggests that DNA plays a functional role beyond the traditionally understood mechanisms. One such example of a phenotypic correlation with DNA content is present in the genus Silene, where a negative correlation between DNA content and flower size exists within and between species. This relationship is consistent with the direction of sexual dimorphism in DNA content (caused by heteromorphic sex-chromosomes) and flower size in the most studied species in the genus: S. latifolia. This thesis takes a comparative approach between two closely related species in the genus (S. latifolia and S. marizii), which differ markedly in their nuclear DNA content, in order to investigate the nature and phenotypic impacts of variation in DNA content. A phenotypic survey from a number of S. marizii populations reveals that the pattern of DNA content variation in this species is very different to that in S. latifolia. In particular, phenotypic correlations with DNA content appear be much weaker, whilst sexual dimorphism in DNA content, when present, appears to occur in either direction. A survey of interspecific hybrids suggests that this may be due to an enlarged S. marizii X-chromosome and that DNA content in hybrids may be biased with regard to their parents. Repetitive elements may be significant constituents of plant genomes. A study of Ty1-copia class retrotransposons in the two species reveals that they are present as a large and highly heterogeneous population. Phylogenetic analysis of these elements suggests a substantial degree of genetic isolation between the two species. Finally, an assessment of the flow-cytometric method, used to estimate DNA content, reveals substantial error associated with the method, but only limited evidence for stoichiometric effects.

The dust particles generated due to mechanical wear of iron ore pellets and clusters formed in molten stainless steel alloyed with rare earth metals (REM) are considered in this study. Firstly, the influence of the characteristics of iron ore pellets, applied load on a pellet bed and partial reduction of the pellets on the size distribution of the generated dust was investigated. Secondly, REM clusters are investigated to evaluate the size distribution of the clusters. Also, an extreme value distribution (EVD) analysis has been applied for the observed REM clusters. The large sized pellets showed 10-20% higher wear rate than small sized pellets during wear in a planetary mill. Moreover, an increase of ~67% was observed in the friction and dust generation in the pellet bed as the applied load increased from 1 to 3 kg. Also, it was observed that a higher friction in the pellet bed can lead to an increased amount of airborne particles. The mechanical wear experiments of pellets reduced at 500 °C (P500) and 850 °C (P850) showed that P500 pellets exhibit ~16-35% higher wear rate than unreduced pellets. For the P850 pellets, the wear is inhibited by formation of a metallic layer at the outer surface of the pellets. The mechanism of dust generation has been explained using the obtained results. A reliable cluster size distribution of REM clusters was obtained by improving the observation method and it was used to explicate the formation and growth mechanism of REM clusters. The results show that the growth of clusters is governed by different types of collisions depending on the size of the clusters. For EVD analysis three different size parameters were considered. Moreover, using the maximum length of clusters results in a better correlation of EVD regression lines compared to other size parameters. Moreover, a comparison of predicted and observed maximum lengths of clusters showed that further work is required for the application of EVD analyses for REM clusters. / Studien fokuserar på två olika typer av mikropartiklar som är valda från olika delar av järn- och ståltillverkningsprocessen. Dessa partiklar är dels stoft som genereras på grund av mekanisk nötning av partiklar och dels klusters som bildas i flytande rostfria stål legerade med sällsynta jordartsmetaller (REM). Inledningsvis så undersöktes inverkan av tre faktorer på storleksfördelningen hos stoft som bildas vid hantering av järnoxidpellets. De undersökta faktorerna inkluderade karakteristiken hos järnoxidpellets, det applicerade trycket på pelletsbädden och den partiella reduktionen av järnoxidpellets. Därefter så utfördes tredimensionella undersökningar av REM kluster som extraherats med hjälp av elektrolytisk extraction för att bestämma storleksfördelningen hos klustren. Dessutom så utfördes en extremvärdesdistribution (EVD) studie för de studerade klustren. En planetkvarn användes för att undersöka inverkan of karakeristiken hos pellets på stoftbildningen. Resultaten visade att storleken på pellets kan påverka nötningshastigheten under dessa försöksförhållanden. Pellets som hade en större storlek (13.5&lt; Deq &lt;15.0 mm) uppvisade en 10 till 20% högre nötningshastighet i jämförelse med mindre pellets (9.5&lt; Deq &lt;12.5 mm). Baserat på analyserna av stoftet som genererades under nötningsexperimenten så konstaterades att nötningsmekanismerna för dessa pellets var abrasions- och kollisionsnötning. En pelletsbädd skapades för att möjliggöra studier av inverkan av ett applicerat tryck på stoftbildningen och friktionskrafterna i en pelletsbädd. Ett varierat tryck på mellan 1 till 3 kg applicerades på pelletsbädden. Resultaten visade att en ökning på ~67% av friktionskraften och stoftbildningen ägde rum när det applicerade trycket ökades från 1 till 3kg. Dessutom så visade resultaten att en högre friktionskraft i pelletsbädden kan resultera in en ökad mängd luftburna partiklar. Den mekaniska nötningen av pellets som reducerats vid 500 °C (P500) och 850 °C (P850) studerades också genom användande av en planetkvarn. Resultaten visade att P500 pellets uppvisade en ~ 16 till 35% högre nötningshastighet i jämförelse med oreducerade referenspellets.  Resultaten för P850 pellets visade att den mekaniska nötningen motverkades genom bildningen av ett metalliskt skikt på den yttre delen av pelletsen. Resultaten visade också att stoftet som bildats pga mekanisk nötning av reducerade pellets innehöll 3 till 6 gånger mer grova partiklar  (&gt;20µm) i jämförelse med stoft som bildats från oreducerade pellets. Slutligen så diskuterades hur dessa resultat kan relateras till industriella förhållanden med avseende på mekanismerna som är involverade i den mekaniska nötningen av pellets samt med avseende på relationen mellan hastigheten av de utgående gaserna och storlken och morfologin hos stoftpartiklarna. Klusters innehållande REM-oxider som extraherats från en 253MA rostfri stålsort undersöktes med användande av en tredimensionell teknik. En trovärdig storleksfördelning av klusters (CSD) erhölls genom att förbättra undersökningsmetoden och denna användes för att studera bildningen och tillväxten av REM oxider. Dessutom så användes cirkularitetsfaktorn hos klusters för att dela in klustren i två olika grupper, vilka bildas och tillväxer enligt olika mekanismer. Resultaten visade också att tillväxten av klusters gynnas av olika typer av kollisioner som beror av av storleken på klusters. För REM-klusters så drogs slutsatsen att turbulenta kollisioner är den huvudsakliga mekanismen som påverkar tillväxten. Avhandlingen behandlar även problemet om hur det är möjligt att hantera synfält där det inte förekommer kluster vid en extremvärdesdistribution (EVD) analys. Tre olika parametrar undersöktes i EVD analysen. Resultaten visar att om den maximala längden på kluster (LC) används i analysen så erhålls den bästa korrelationen gällande regressionslinjen för en EVD analys. Specifikt så var R2 värdet upp till 0.9876 i jämförelse med de andra storleksparametrarna som har värden i intervallet 0.9656 – 0.9774. Slutligen så visar resultaten från en jämförelse mellan beräknade och observerade maximala klusterlängder att EVD analyser för studier av REM kluster behöver undersökas ytterligare i framtiden. / <p>QC 20161128</p>