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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

An experimental study of abattoir wastewater treatment from an economic perspective.

Verhoef, Geoffrey D., mikewood@deakin.edu.au January 2002 (has links)
The most cost effective treatment scheme for effluent from Midfield Meats, an abattoir in Warrnambool, Australia, was evaluated via a series of laboratory and commercial scale experiments. Effectiveness was measured in terms of suspended solids (SS) and biological oxygen demand (BOD) reduction. Economic assessment was based on predicted reduction in trade waste charges versus infrastructure and running costs. From the range of potential treatment technologies, those deemed most appropriate for trialling included pre-screening, sedimentation, coagulation and flocculation treatment and dissolved air floatation (DAF). Prior to evaluation of treatment types, flow, loads and contaminant characterisation of the waste streams was conducted to aid in selection of treatment type and capacity. Prescreening was found to be the most cost effective, followed by sedimentation, coagulation and flocculation treatment and finally DAF. The most economical treatment scheme that satisfied the requirements of Midfield Meats included a combination of prescreening and sedimentation. DAF and coagulation and flocculation treatment satisfactorily treated the wastewater, however were not cost effective under the current trade waste agreement.
2

Where did they come from? Why did they go? How engineering students’ perceptions cultivate experiences and influence behaviors

Vick, Sara Campbell 12 May 2023 (has links) (PDF)
Engineering undergraduate students have opinions and perceptions of engineering disciplines and engineering undergraduate students do not always matriculate and graduate in precisely the same discipline. Understanding how these two characteristics of engineering undergraduate students interact to inform behaviors is important for engineering educators and administrators to increase and improve recruitment and retention among their students. This dissertation approached each characteristic of engineering students, first separately and then together. A nationwide survey of undergraduate engineering students found significant differences in how students perceive various engineering disciplines along several paired-term anchored scales. These differences were equally significant when scores were considered in terms of discipline-membership. Membership was found to lead to higher scores for Difficulty and Friendliness compared to scores of non-members for any given specific discipline. Using historical data, transfer paths of students into, out of, or within engineering were identified by frequency of occurrence as either the origin of a transfer or the destination of a transfer. Industrial Engineering was found to be considerably more frequently experienced as a destination of transfers, regardless of whether the origin degree program was another engineering discipline or from outside of engineering. Conversely, Aerospace Engineering was considerably more frequently experienced as an origin of transfers. Additionally, the transfer path relationship between Computer Engineering and Electrical Engineering was investigated. Combining these two characteristics of engineering students—that of having opinions of engineering disciplines and that of having the potential to transfer between degree programs— an ethnographic research methodology was implemented. Factors unrelated to grade performance were identified as common program-change instigators, including personal interest considerations and predicted career opportunities. Ultimately, this dissertation contributes to an understanding of how perceptions of engineering disciplines and degree program transfer behavior affects undergraduate engineering student experiences.
3

Diversitet av mossor och lavar på åkerholmar i ett öppet och ett skogsdominerat landskap / Diversity of mosses and lichens on midfield islets in an open and a forest-dominated landscape

Qasim, Amina January 2015 (has links)
De ekologiskt betydelsefulla småbiotoperna blir allt färre i det moderna jordbruket på grund av intensifieringen av jordbrukslandskapet som resulterat i ett allt mer fragmenterat landskap. För att kunna ge småbiotoper, såsom åkerholmar, ett optimalt skydd behövs flera studier om organismerna på holmarna, deras diversitet och spridning. I denna undersökning studeras artrikedomen av mossor och lavar på busk- och trädbekädda samt öppna åkerholmar i ett öppet- och ett skogsdominerat landskap. Analysen av artrikedom i studien tyder på att de finns fler arter av mossor och lavar i det öppna landskapet i förhållande till det skogsdominerade landskapet samt på de åkerholmarna som saknade busk- och trädvegetation. Dessa miljöer består av torr och stenig mark och växer igen relativt långsamt, vilket är gynnsamt för vissa mossor och lavar. Det fanns ingen signifikant korrelation mellan diversitet och storleken på åkerholmarna eller mellan diversitet och holmarnas avstånd till skog. Antalet arter i ett habitat kan bero på regionala artpoolen samt antalet potentiella kolonisatörer men även lokala processer. Vidare är det viktigt att nämna att studien tyder på att diversitet av mossor och lavar påverkas av förhållandena på holmarna, såsom busk- och trädtäckningen. Detta i kombination med en variation inom dessa små biotoper kan skapa goda förutsättningar för ett landskap med hög diversitet. / The ecologically important small remnant habitats are becoming fewer in modern agriculture due to the intensification of agricultural landscapes that have resulted in an increasingly fragmented landscape. In order to provide an ideal conservation framework for small habitats, such as midfield islets, several studies about the organisms on the islets, their diversity and distribution are needed. In this study I investigated the diversity of mosses and lichens on open midfield islets with and without shrubs and trees in an open and a forest-dominated landscape. The analysis of species diversity in the study suggests that, overall; there are more species of mosses and lichens in the open landscape in relation to the forest-dominated landscape, and on the opened islets lacking shrub and tree vegetation. These environments consist of dry and rocky soils and overgrow relatively slowly, which is favourable for mosses and lichens. There was no significant correlation between diversity and size of the midfield islets or their distance to forest. The number of species in a habitat may depend on regional species pool and the number of potential colonizers but also local processes. Furthermore, it is important to mention that the study suggests that the diversity of mosses and lichens is influenced by the conditions on the midfield islands, such as shrub and tree cover. These conditions, combined with a variation within these small habitats can create good conditions for a landscape with high diversity.
4

CSR communication of Premier League clubs on social media. The impact of winning and revenue

Kunst, Felix January 2022 (has links)
Introduction: In recent years, social media communication has significantly affected the way organizations are sharing information. Social media platforms are shown to be one of the most important forms of communication also for the intent of Corporate Social Responsibility. The purpose of this study was to find out how often CSR is shared across Facebook, Twitter, Instagram, and TikTok and if differences exist between those platforms in frequency, choice of topic, and engagement of fans. Furthermore, the influence of being a winning, midfield, and losing team, and high and low revenue was investigated. Methods: A quantitative content analysis study was chosen as the study design. On the four mentioned social media platforms data was manually collected for Premier League clubs and coded into topics of CSR. The engagement of fans was collected with likes, comments, and shares on the relevant platforms. Results: 6879 total posts were investigated including 272 posts related to CSR content. The highest ratio for CSR posts showed Facebook (5,0%), followed by Twitter (3,7%), then Instagram (3,4%), and at last TikTok (0,8%). However, the highest number of posts was shared by Twitter, followed by Facebook, Instagram, and TikTok. The topics shared the most on Twitter and Facebook are Public Policy, Safety, and Diversity. On Instagram as well Public Policy, Diversity but also Religion posts were shared the most. TikTok showed only one post related to the topic of Religion. The engagement of fans showed that Twitter has the highest engagement compared to a non-CSR-related post, closely followed by Instagram. An ANOVA analysis showed that winning teams and losing teams share significantly more CSR content than midfield teams. It was also discovered that teams with high revenue post more CSR than teams with low revenue. Discussion/Conclusion: New and major findings of this study suggest that teams in the European market have different factors that can influence the teams sharing behavior than teams from the North American market. The most interesting findings of this study show that revenue and winning may positively influence CSR sharing behavior. These insights should help understand CSR communication in sports organizations and displays the potential new platforms like TikTok and Instagram have.
5

The role of midfield islets in pest control

Sigfridsson, Sabine January 2013 (has links)
During last century rising populations and changed market preferences have led to large structuralchanges in agriculture in the developed world. Most conventional cultivation methods involve theproduction of few monoculture crops within a homogenous landscape, where pesticides and inorganicfertilizers are used to increase yields. The cereal aphid Rhopalosiphum padi (L.) is a pest in cerealsresulting in large economic losses for farmers throughout Europe, and are currently removed withchemical pest control. However, the pesticides also affect existing ecosystem services like potentiallypest-controlling insects as well as the surrounding environment negatively. According to previousstudies higher landscape diversity leads to a higher diversity of natural enemies to pest insects, but nostudy has investigated if the pest control is enhanced around non-crop remnants such as midfield islets(MI). This thesis investigates (i) if MI will reduce the number of aphids in crop field, (ii) if larger MIwill be more effective than smaller MI by having higher aphid predation rate, and (iii) if larger MI willprovide a more effective reduction of pest insects over a longer distance from edge. To assess thepotential for pest control, aphids were glued on papers and placed at ground level in crop fields andaround MI in nine fields. The collected data was processed statistically, and the result demonstratesthat MI play an important role by providing habitats for natural enemies to pests. The increased size ofMI have a positive effect of number of aphids consumed around MI, however the distance from edgewas not significance. This study highlights the value of MI in crop fields as an existing ecosystemservice in biological pest control. The naturally occurring predators are able to reduce R.padi andthereby minimize the need for insecticide applications. / Ökat befolkningstryck och större efterfrågan av jordbruksprodukter på marknaden har det senasteseklet lett till stora förändringar i västvärldens jordbrukslandskap. Odlingslandskapet är idaghomogent och monokulturellt där besprutningsmedel används för att ge större avkastning iproduktionen. Skadeinsekten havrebladlus (Rhopalosiphum padi) angriper vårgrödor vilket leder tillstora ekonomiska förluster för bönder runtom i Europa. Pesticider används för att reducera angreppenmen påverkar även miljön negativt samt existerande ekosystemtjänster, såsom naturliga fiender sombiologiskt kan begränsa skadeinsekters angrepp. Tidigare studier visar att heterogena landskap har enhög biologisk mångfald, men ingen studie har undersökt åkerholmars (ÅH) eventuella potential förbiologisk bekämpning av skadeinsekter i säd. Denna studie undersöker därför (i) om ÅH leder tillökad reducering av havrebladlöss i säd, (ii) om större ÅH är mer effektiva än mindre i frågan ompestreducering, samt (iii) om större ÅH begränsar lusangrepp längre ut i fält från ÅH:s kant än mindreholmar. Studiens hypoteser testades genom experiment utförda i nio fält med vårgrödor där lössklistrades på etiketter som placerades ut i omgivande fält. Dessa samlades in efter tjugo fyra timmarför att studera antal löss konsumerade i relation till ÅH. Det insamlade materialet är bearbetatstatistiskt och resultatet visar att ÅH spelar en betydande ekologisk roll för naturliga fiender tillskadeinsekten havrebladlus. Fler löss konsumerades runt större ÅH än de med mindre yta eller i de fältutan ÅH. Däremot har avståndet från ÅH en mindre betydelse, vilket indikerar att pestreduceringen ärmest effektiv nära stora ÅH. Denna studie synliggör värdet av existerande ÅH som inhysernyttoinsekter i jordbrukslandskapet, samt att heterogena landskap har högre potential för en mernaturlig skadedjursbekämpning. Naturliga fiender är därmed en existerande ekosystemtjänst som kanbegränsa bladlusangreppen (R.padi), som i sin tur ger möjligheten att reducera användandet avbekämpningsmedel, vilket för oss närmare miljömålet ”en giftfri miljö”.
6

Small remnant habitats : Important structures in fragmented landscapes

Lindgren, Jessica January 2017 (has links)
The world-wide intensification of agriculture has led to a decline in species richness due to land use change, isolation, and fragmentation of natural and semi-natural habitats in agricultural and forestry landscapes. As a consequence, there is a current landscape management focus on the importance of green infrastructure to mitigate biodiversity decline and preserve ecosystem functions e.g. pollination services and pest control. Even though intensification in agriculture has been ongoing for several hundreds of years, remnant habitats from earlier management practices may still be remaining with a surprisingly high plant richness. Preserving these habitats could help conserving plant species richness in agricultural landscapes, as well as other organisms that are dependent on plants for food and shelter. In this thesis I focus on two small remnant habitats; midfield islets and borders between managed forest and crop field in southeastern Sweden. In the past, both habitats were included in the grazing system and therefore often still have remnant population of grassland specialist species left today. I have used these two remnant habitats as model habitats to investigate the effect of landscape factors and local factors on species richness of plants, flower morphologies and plants with fleshy fruits. Additively, I analysed the effect of surrounding landscape and local openness on the functions; pollination success, biological pest control of aphids and seed predation on midfield islets. One of my studies showed that spatial distribution and size of the habitat affected plant species richness. Larger habitat size and higher connectivity between habitats increased species richness of plants in the habitats. Openness of the habitats was shown to be an important factor to increase species richness and richness of flower morphologies, both on midfield islets and in forest borders. Even though midfield islets had the highest species and morphology richness, both habitat types are needed for habitat complementary as forest borders have more plants with fleshy fruits and a higher richness of plant species that flowers in spring/early summer. It was also shown that a more complex forest border, not just with gaps in the canopy, but also with high variation in tree stem sizes increases plant species richness in the field layer. The conclusion is that by managing small remnant habitats to remain or become more semi-open and complex in their structure, would increase species richness of plants, grassland specialist species, and flower morphologies. It would also increase some ecosystem functions as seed predation and biologic pest control of aphids are more effective close to trees. If both midfield islets and forest borders would be managed to be semi-open, the area and connectivity of semi-open habitat would increase in the agricultural landscape, which may also improve pollination success as the connectivity between populations has a possibility to increase. Grassland specialist species are clearly abundant in the small remnant habitats. As the decline of semi-natural grasslands is causing a decline in grassland specialists’ species, not only plants, I recommend that small remnant habitats are included in conservation and management plans and strategies to improve habitat availability and connectivity for grassland species in agricultural landscapes. / <p>Research funder Ekoklim. Project:4339602.</p><p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 4: Manuscript.</p>

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