Airfoil Optimization Through Differential Evolution

This thesis presents the development of a numerical optimization algorithm for airfoils, and how it can be used in design of wind turbine blades. It was found that the developed algorithm successfully improves the goal parameters under given conditions and constraints. This research was conducted on behalf of Winfoor AB who has developed a conceptually new blade design, in which every single blade is made up of three individual blades, kept together by rods in a truss like manner. Their wish was to develop a new airfoil for their turbine, with higher performance and a more docile stall, and yet remaining a high airfoil thickness in order to not alter structural stability. The task was conducted by describing the airfoils with B-splines and writing an optimization algorithm in MATLAB in which the flow characteristics of the airfoils were determined by the external software XFOIL. This thesis shows how to characterize numerical optimization problems, what differential evolution is and how it can be implemented in a MATLAB-code, how airfoils can be described with B-splines, the usage of XFOIL and how penalty functions can be imposed for constrained optimization problems, to mention some of the wisdoms this work has brought. This research is important as numerical optimization of airfoils is not yet the standard method for airfoil design, and thus it can possibly contribute with valuable insights and results to further development of airfoil optimization

Novel regulators of human gonadal development

The production of viable germ cells during human embryonic development determines adult reproductive success. This is particularly true for females, as development of germ cells (GCs) into primordial follicles before birth is imperative for future fertility. During fetal development GCs migrate to the genital ridge to form the gonad, after which several tightly regulated events, including proliferation, differentiation, and association with somatic cells, must occur to form a functional gonad. In the ovary these processes also include the initiation and subsequent arrest of meiosis. These developmental processes are orchestrated by local autocrine and paracrine factors, many of which remain to be identified in the human. In order to decipher further the pathways by which the gonad and GCs develop, potential regulators including prostaglandin (PG) E2, the interleukin (IL)6-type cytokines, and the prokinetecins (PROKs), were examined in the human fetal ovary and PROKs in the human fetal testis. Patterns of gene expression, protein localisation, function, and interaction of the potential mediators throughout human development (8-20 weeks gestation) were determined. Primary fetal tissue was investigated, in addition to immortalized GCs (T-Cam2 cells) and a murine model of fetal ovarian development. PGE2 interacts with known regulators of GC development in non-reproductive organs. It was postulated PGE2 may regulate GC progression by modulating these factors. Examination of PGE2 receptors and precursor enzymes in the fetal ovary revealed that all were present and some were developmentally regulated, with mRNA expression increasing with gestation. These developmentally regulated components were localised to the GCs. The PGE2 receptors were among those differentially expressed, with one localised solely to mature GCs. Culture of human fetal ovary confirmed that PGE2 regulates known regulators of GC development, increasing expression of survival and anti-apoptotic factors. To test the hypothesis that PGE2 is necessary for female GC development, paracetamol, an inhibitor of PGE2 precursor enzymes, was utilised in a murine model of fetal exposure. Fetal ovaries from this experiment displayed disruption of normal development. The IL6-type cytokines are also postulated to be involved in early gonad development, and are known to regulate proliferation and differentiation of mouse embryonic stem and GCs in vitro. A significant increase in transcript levels of the shared receptor components was determined in second trimester human ovaries, as well as developmental increases of several of the IL6-type ligands. Both common receptor components were located specifically in the GCs identifying them as the target of IL6 action in the human fetal ovary. The PROKs regulate cell migration, proliferation and differentiation, and modulate secretion of PGE2 and expression of some IL6-type cytokines. To-date, PROKs have not been examined in the human fetal gonad. Transcript levels were higher in the fetal testis compared to the ovary, with receptor and ligand components increasing with gestation. Most components also increased with gestation in the ovary. However, location of PROK components was strikingly different between the two tissues, with GCs being the primary target of PROK action in the fetal ovary, and Leydig and interstitial cells being the target in the testis. PROKs interaction with other regulators of gonad development was examined utilising a GC line in the case of the ovary and primary interstitial cell cultures in the case of the testis. These studies have identified new factors involved in human fetal gonad development, and how they interact with known regulatory pathways of development

Fracture resistance of porcelain-veneered gold-alloy and zirconia molar crowns

Abstrakt Syfte:Studiens syfte var att utreda maxlasttoleransen mellan yttria-stabiliserad zirkoniumdioxid- (Y-TZP) och metallkeramiska- (MC) molarkronor med en ny design på in vitro belastningsformen. En stålkula användes för att utöva last på kusparna istället för i fissuren för att framställa en sprickbildning liknande den som ses kliniskt. Materialochmetod:26 kronor tillverkades, varav 13 högädla MC och 13presintrade Y-TZP. 7 av MC göts av 50% tidigare icke-gjuten och 50% omgjuten legering medan de kvarvarande 6 göts av 100% tidigare icke gjuten legering. Kronorna täcktes av ett fasadporslinoch cementerades på stansar av ett resinmaterial. Av de 26 kronorna genomgick 24 förbelastingstester och belastades slutligen till fraktur. Resultat: MC klarade signifikant högre belastningar än Y-TZP, P>0,001. Frakturerna skiljde sig också grupperna emellan där MC-gruppen uppvisade enbart adhesiva frakturer av fasadporslinet under det att Y-TZP-gruppen uppvisade kohesiva brott i ytporslinet undantaget en Y-TZP-krona som uppvisade total fraktur. Ingen signifikant skillnad kunde ses mellan MC-kronor bestående av enbart tidigare icke gjuten legering och MC-kronor med 50% omgjuten legering, P=0,370. Konklusion: MC-kronor klararsignifikant högre belastningar än Y-TZP-kronor och testet genererar kliniskt relevanta frakturer av ytporslinet snarare än totala frakturer. Frakturbeteendet skiljer sig mellan MC och Y-TZP där MC uppvisar endast adhesiva fraktureroch Y-TZP främst kohesiva brott av ytporslinet

Agile requirements engineering in practice : Does practice follow the literature?

Att arbeta agilt är idag vanligt förekommande inom IT-branschen där företag ständigt måste anpassa sig till förändringar. Scrum är idag den främst tillämpade agila metoden och har stark koppling till utvecklingsprojekt och kravhantering. Trots detta finns det få empiriska studier om Scrum och det finns även en brist på jämförande studier som ställer kravhantering i praktiken mot det som finns formulerat i litteraturen. Vi har därför i denna studie undersökt hur arbetet med kravhantering i utvecklingsprojekt bedrivs i praktiken hos en organisation som arbetar efter Scrum och jämfört om arbetet utförs i enlighet med det som står i litteraturen. Vi har även tittat på vilka problem och svårigheter som kan uppkomma i kravhanteringsarbetet samt vilka aspekter som utövarna i praktiken betraktar som viktigast. För att ta reda på hur arbetet faktiskt genomförs intervjuade vi fyra personer på företaget Arris, alla med olika befattningar och kopplingar till kravhantering.   Slutsatsen av undersökningen visar att kravhanteringsarbetet i praktiken i de flesta aspekter överensstämmer med det som formuleras i litteraturen. Det finns dock områden som ej går helt i linje, dokumentation av krav är ett sådant.Working agile is nowadays common within the IT industry where companies constantly have to cope and adapt to change. Scrum is today the most applied agile method and is strongly linked to development projects and requirements engineering. Despite this, there are few empirical studies on Scrum and it also lacks comparative studies where requirements engineering in practice are compared to what is formulated in the literature. As a result of this, we have in this survey, examined how requirements engineering in an organization that is using Scrum is conducted in practice in accordance to what is formulated in the literature. We also identified problems and difficulties that may arise in the work with requirements engineering and also which aspects practitioners considers as most important. In order to be able to realize this study we interviewed four practitioners from Arris, all with different positions and connections to requirements engineering. The conclusion of this study shows that the requirements engineering in practice in most aspects is consistent with what the literature advocates. However, there are areas that not fully correspond to what is written in the literature, documentation of requirements is one such area

Utveckling av Webbportal för Vårdcentralen Aroma i Vetlanda

This exam paper has been made with the health care center Aroma in Vetlanda. The work was to deliver a complete web portal with an integrated booking system. The objectives were to provide a complete informative website for Aromas users with the option to make an appointment for a vaccination or health certificate, order prescriptions and get update information directly published by Aromas staff. And to give the staff of Aroma a graphical Web interface to manage the content and the booking system.The report goes through the basic language used and why. Further it takes up it how works and how the final product looks and behaves.Detta examensarbete har gjorts med Vårdcentralen Aroma i Vetlanda.  Arbetet gick ut på att leverera en komplett webbportal med integrerat bokningssystem. Målen var att kunna leverera en informativ webbplats för Aromas användare med möjlighet att boka tid vaccinationer och intyg, beställa recept och ta del av nyheter direkt publicerade av deras personal. Samt att ge personalen ett grafiskt webbgränssnitt för att hantera allt innehåll och bokningssystemet.   Rapporten går grundläggande igenom vilka språk som använts och varför. Vidare redogörs hur arbetet har utförts och hur den slutliga produkten ser ut och fungerar

The experienced value journey of slow fashion consumers: from pre-purchase to post-purchase of apparel

Purpose: The purpose of this research is to explore how consumers of slow fashion experience value of apparel in relation to price, quality, appearance and style, awareness, and trust.Research questions: How do the extrinsic cues in relation to slow fashion influence the value journey of slow fashion consumers? What is the experienced value journey of slow fashion consumers from pre-purchase to post-purchase of apparel?Methodology: data was collected through semi-structured interviewing with eight participantsFindings: The research identified that slow fashion consumers undergo a value journey based on five components: their knowledge, altruistic concerns, personal investment, expectations, and their emotional connection. Their knowledge is formed by how much the slow fashion consumers know about the production process of the apparel, the material quality of the apparel, and themselves in terms of their personal preferences. Their altruistic concerns involve influences how they consume and use clothes based on their ethics. Their personal investment is determined by how much time, effort, and resources they are willing to spend on pieces of apparel. The slow fashion consumer then set an expectation on how well the piece of apparel satisfies these three components through its usage in a post-purchase context. If the piece of apparel exceeds their expectations, they form an emotional connection. This emotional connection again determines their next line of consumption of apparel in a pre-purchase context. These five components determine therefore the process of slow fashion consumers’ perceived value pre-purchase to the perceived value-in-use post-purchase

The experienced value journey of slow fashion consumers: from pre-purchase to post-purchase of apparel

Purpose: The purpose of this research is to explore how consumers of slow fashion experience value of apparel in relation to price, quality, appearance and style, awareness, and trust.Research questions: How do the extrinsic cues in relation to slow fashion influence the value journey of slow fashion consumers? What is the experienced value journey of slow fashion consumers from pre-purchase to post-purchase of apparel?Methodology: data was collected through semi-structured interviewing with eight participantsFindings: The research identified that slow fashion consumers undergo a value journey based on five components: their knowledge, altruistic concerns, personal investment, expectations, and their emotional connection. Their knowledge is formed by how much the slow fashion consumers know about the production process of the apparel, the material quality of the apparel, and themselves in terms of their personal preferences. Their altruistic concerns involve influences how they consume and use clothes based on their ethics. Their personal investment is determined by how much time, effort, and resources they are willing to spend on pieces of apparel. The slow fashion consumer then set an expectation on how well the piece of apparel satisfies these three components through its usage in a post-purchase context. If the piece of apparel exceeds their expectations, they form an emotional connection. This emotional connection again determines their next line of consumption of apparel in a pre-purchase context. These five components determine therefore the process of slow fashion consumers’ perceived value pre-purchase to the perceived value-in-use post-purchase

Fracture of porcelain-veneered gold-alloy and zirconia molar crowns using a modified test set-up

Objective: to compare fracture load and fracture mode of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and metal-ceramic (MC) molar crowns using a modified test set-up to produce fractures similar to those seen in vivo, i.e. fractures of the veneering material rather than complete fractures. Materials and methods: 13 high-noble-alloy MC and 13 Y-TZP molar crowns veneered with porcelain were manufactured. The crowns were artificially aged before final load to fracture. Load was applied using a 7mm diameter steel ball exerting force on the cusps with stresses directed toward the core-veneer interface. Fracture surface analysis was performed using light- and scanning electron microscopy. Results: The test design produced fractures of the veneering material rather than complete fractures. MC crowns withstood significantly (p>.001) higher loads (mean 2155 N) than Y-TZP (mean 1505 N) crowns yet both endure loads sufficient for predictable clinical use. Fracture mode differed between MC and Y-TZP. MC crowns exhibited fractures involving the core-veneer interface but without core exposure. One Y-TZP crown suffered a complete fracture, all others displayed fractures of the veneering material involving the core-veneer interface with core exposure. Conclusions: The test set-up produces fractures similar to those found in vivo and may be useful to evaluate the core-veneer interface of different material systems, both metals and ceramics. The study confirms suggestions from previous studies of a weaker core-veneer bond for Y-TZP compared to MC crowns

Fracture of porcelain-veneered gold-alloy and zirconia molar crowns using a modified test set-up

Objective: to compare fracture load and fracture mode of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and metal-ceramic (MC) molar crowns using a modified test set-up to produce fractures similar to those seen in vivo, i.e. fractures of the veneering material rather than complete fractures. Materials and methods: 13 high-noble-alloy MC and 13 Y-TZP molar crowns veneered with porcelain were manufactured. The crowns were artificially aged before final load to fracture. Load was applied using a 7mm diameter steel ball exerting force on the cusps with stresses directed toward the core-veneer interface. Fracture surface analysis was performed using light- and scanning electron microscopy. Results: The test design produced fractures of the veneering material rather than complete fractures. MC crowns withstood significantly (p>.001) higher loads (mean 2155 N) than Y-TZP (mean 1505 N) crowns yet both endure loads sufficient for predictable clinical use. Fracture mode differed between MC and Y-TZP. MC crowns exhibited fractures involving the core-veneer interface but without core exposure. One Y-TZP crown suffered a complete fracture, all others displayed fractures of the veneering material involving the core-veneer interface with core exposure. Conclusions: The test set-up produces fractures similar to those found in vivo and may be useful to evaluate the core-veneer interface of different material systems, both metals and ceramics. The study confirms suggestions from previous studies of a weaker core-veneer bond for Y-TZP compared to MC crowns

Fracture of porcelain-veneered gold-alloy and zirconia molar crowns using a modified test set-up

Objective: to compare fracture load and fracture mode of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) and metal-ceramic (MC) molar crowns using a modified test set-up to produce fractures similar to those seen in vivo, i.e. fractures of the veneering material rather than complete fractures. Materials and methods: 13 high-noble-alloy MC and 13 Y-TZP molar crowns veneered with porcelain were manufactured. The crowns were artificially aged before final load to fracture. Load was applied using a 7mm diameter steel ball exerting force on the cusps with stresses directed toward the core-veneer interface. Fracture surface analysis was performed using light- and scanning electron microscopy. Results: The test design produced fractures of the veneering material rather than complete fractures. MC crowns withstood significantly (p>.001) higher loads (mean 2155 N) than Y-TZP (mean 1505 N) crowns yet both endure loads sufficient for predictable clinical use. Fracture mode differed between MC and Y-TZP. MC crowns exhibited fractures involving the core-veneer interface but without core exposure. One Y-TZP crown suffered a complete fracture, all others displayed fractures of the veneering material involving the core-veneer interface with core exposure. Conclusions: The test set-up produces fractures similar to those found in vivo and may be useful to evaluate the core-veneer interface of different material systems, both metals and ceramics. The study confirms suggestions from previous studies of a weaker core-veneer bond for Y-TZP compared to MC crowns